U.S. President Joe Biden said on Tuesday Ukraine "stands strong" a year after the Russian invasion and that Moscow would never defeat its neighbour, after the Kremlin suspended a landmark nuclear arms control treaty over the West's support for Kyiv.

Hours before Biden spoke in Poland following a surprise visit to Ukraine, Russian President Vladimir Putin vowed that Moscow would achieve its objectives in Ukraine and accused the West of plotting to destroy Russia.

Alleging that the United States was turning the Ukraine war into a global conflict, Putin said Russia was suspending participation in the 2010 New START treaty , its last major arms control treaty with Washington.

Putin, upping the ante in what has become the biggest confrontation with the West since the 1962 Cuban Missile Crisis, also announced that new strategic systems had been put on combat duty and threatened to resume nuclear tests.

Biden proclaimed "unwavering" support for Kyiv and a commitment to bolstering NATO's eastern flank facing Russia, while rejecting Moscow's contention that the West was plotting to attack Russia.

"One year ago, the world was bracing for the fall of Kyiv," Biden said at Warsaw's Royal Castle. "I can report: Kyiv stands strong, Kyiv stands proud, it stands tall and, most important, it stands free.

"When President Putin ordered his tanks to roll into Ukraine, he thought we would roll over. He was wrong," he said.

U.S. Secretary of State Antony Blinken called Putin's suspension of its role in New START "deeply unfortunate and irresponsible". NATO Secretary-General Jens Stoltenberg said it made the world a more dangerous place, and urged Putin to reconsider.

Signed by then-U.S. President Barack Obama and his Russian counterpart Dmitry Medvedev in 2010, the treaty caps the number of strategic nuclear warheads that the countries can deploy.

Due to expire in 2026, it allows each country to physically check the other's nuclear arsenal, although tensions over Ukraine had already brought inspections to a halt.

The Russian leader said, without citing evidence, that some in Washington were considering breaking a moratorium on nuclear testing. " ... If the United States conducts tests, then we will. No one should have dangerous illusions that global strategic parity can be destroyed," Putin said.

"A week ago, I signed a decree on putting new ground-based strategic systems on combat duty."

It was not immediately clear which systems he meant.

Putin said Ukraine had sought to strike a facility deep inside Russia where it keeps nuclear bombers, a reference to the Engels air base. Ukraine has followed a policy of not publicly claiming responsibility for any attacks on Russian soil.

Putin, who has over the past year repeatedly hinted that Russia could use a nuclear weapon if threatened, was in effect saying that he could dismantle the architecture of nuclear arms control unless the West backs off in Ukraine.

Putin said the conflict had been forced on Russia, particularly by NATO's eastward expansion since the Cold War.

"The people of Ukraine have become the hostage of the Kyiv regime and its Western overlords, who have effectively occupied this country in the political, military and economic sense."

Kyiv and Western leaders such as Biden, who visited the Ukrainian capital on Monday, reject that narrative as an unfounded pretext for a land grab in a fellow former Soviet republic that Putin calls an artificial state, and say he must be made to lose his gamble on invasion.

Russia has suffered three major battlefield reverses in Ukraine but still control around a fifth of its neighbour. Tens of thousands of Ukrainian civilians and soldiers on both sides have been killed.

A senior aide to Ukraine's president said Putin's speech showed he had lost touch with reality.

"He is in a completely different reality, where there is no opportunity to conduct a dialogue about justice and international law," Mykhailo Podolyak, a political adviser to Ukrainian President Volodymyr Zelenskiy, told Reuters.

"Russia is at a dead end. In the most desperate situation. Everything that Russia will do next will only worsen its situation."

As Putin was speaking, at least one Russian rocket slammed into a busy street in the southern Ukrainian city of Kherson, killing six people.

Ukraine's military and city authorities said 12 others were wounded in the attack, which left a pool of blood on the pavement beside a mangled bus stop.

Local authorities said Kherson came under fire from multiple rocket launchers as Putin described the West as the aggressor in Ukraine and depicted Russia as not waging war on the Ukrainian people. Russia did not immediately comment on the incident.

Moscow has denied deliberately targeting civilians in its "special military operation", but cities across Ukraine have been devastated in missile and drone attacks and thousands of civilians have been killed.

The West has pledged tens of billions of dollars in military aid to Kyiv.

Speaking for an hour and 45 minutes, Putin vowed that Moscow would achieve its aims in Ukraine and thwart the U.S.-led NATO alliance in the process.

"They intend to transform a local conflict into a phase of global confrontation," he said. "This is exactly how we understand it all and we will react accordingly, because in this case we are talking about the existence of our country."

U.S. President Joe Biden delivers remarks ahead of the one year anniversary of Russia's invasion of Ukraine, outside the Royal Castle, in Warsaw, Poland, February 21, 2023. REUTERS/Evelyn Hockstein Ukrainian servicemen ride a self-propelled howitzer outside the town of Siversk, amid Russia's attack on Ukraine, in Donetsk region, Ukraine February 20, 2023. REUTERS/Yevhen Titov Russia's President Vladimir Putin takes part in an event marking Gazprom's 30th anniversary, via video link at a residence outside Moscow, Russia February 17, 2023. Sputnik/Mikhail Metzel/Pool via REUTERS U.S. President Joe Biden walks with Ukrainian President Volodymyr Zelenskiy at St. Michael's Golden-Domed Cathedral during an unannounced visit, in Kyiv, Ukraine, Monday, Feb. 20, 2023. Evan Vucci/Pool via REUTERS U.S. President Joe Biden walks with Ukrainian President Volodymyr Zelenskiy during an unannounced visit, in Kyiv, Ukraine, Monday, Feb. 20, 2023. Evan Vucci/Pool via REUTERS U.S. President Joe Biden embraces Ukraine's President Volodymyr Zelenskiy as they visit the Wall of Remembrance to pay tribute to killed Ukrainian soldiers, amid Russia's attack on Ukraine, in Kyiv, Ukraine February 20, 2023. Ukrainian Presidential Press Service/Handout via REUTERS. Ukrainian service members patrol an area in the town of Siversk, amid Russia's attack on Ukraine, in Donetsk region, Ukraine February 20, 2023. REUTERS/Yevhen Titov

Some Chinese provinces are giving young newlyweds 30 days of paid leave in the hope of encouraging marriage and boosting a flagging birth rate, the Communist Party mouthpiece People's Daily Health said on Tuesday.

China's minimum paid marriage leave is three days, but provinces have been able to set their own more generous allowances since February.

The northwestern province of Gansu and the coal-producing province of Shanxi now give 30 days, while Shanghai gives 10 and Sichuan still only three, according to the People's Daily Health.

"Extending marriage leave is one of the effective ways of increasing the fertility rate," Yang Haiyang, dean of the Social Development Research Institute of Southwestern University of Finance and Economics, was quoted as saying.

"The extension of marriage leave is mainly in some provinces and cities with relatively slow economic development," he said, adding that there was an urgent need to both expand the labour force and stimulate consumption.

Yang said a host of other supporting policies were still needed, including housing subsidies and paid paternity leave for men.

China's population fell last year for the first time in six decades, according to official data - a turning-point that is expected to mark the start of a long period of decline.

Last year, China recorded its lowest ever birth rate, of 6.77 births per 1,000 people.

Much of the downturn is the result of a "one child" policy imposed between 1980 and 2015, and a surge in education costs that has put many Chinese off having more than one child, or even having any at all.

A newly wed couple pose for pictures on Valentine's Day at a marriage registration office in Hangzhou, Zhejiang province, China February 14, 2023. China Daily via REUTERS Couples prepare to have their photo taken during a wedding photo shoot on a street, amid the coronavirus disease (COVID-19) pandemic, in Shanghai, China May 31, 2021. REUTERS/Aly Song/File Photo A couple pose for pictures during a wedding photo shoot on Yalong Bay beach in Sanya, Hainan province, China November 26, 2020. Picture taken November 26, 2020. REUTERS/Tingshu Wang/File Photo

U.S. stock index futures fell on Tuesday as fears that interest rates will remain higher for longer gripped traders returning from a long weekend, while disappointing results from Home Depot added to the gloomy mood.

The No. 1 U.S. home improvement chain (HD.N) dropped 3.8% in premarket trading after its fourth-quarter comparable sales fell short of estimates on higher supply-chain costs and weak demand due to inflation.

Investors will be focusing on retail giant Walmart Inc's (WMT.N) results due later in the day.

At 6:34 a.m. ET, Dow e-minis were down 264 points, or 0.78%, S&P 500 e-minis were down 30.75 points, or 0.75%, and Nasdaq 100 e-minis were down 110.25 points, or 0.89%.

The U.S. stock market got a lift this year from its worst annual showing in more than a decade in 2022, as investors were hopeful that the central bank's rate hiking cycle was nearing its end.

However, recent economic data points to a resilient economy with inflation far from the Fed's 2% target, raising bets for two or three more 25 basis point hikes and lower chances of rate cuts at year-end.

Money market participants see the benchmark level peaking to a 5.3% in July, and staying near those levels throughout the year.

Yield on the U.S. benchmark 10-year Treasury note edged higher, in turn pressuring rate-sensitive growth stocks.

Apple Inc (AAPL.O) , Amazon.com Inc (AMZN.O) , Microsoft Corp (MSFT.O) and Google-parent Alphabet Inc (GOOGL.O) fell between 1% and 1.4% in premarket trading as yield on the benchmark 10-year Treasury note climbed.

Traders find government bonds as a safe alternative to investments in riskier assets like megacap firms.

In a bright spot, Meta Platforms Inc (META.O) added 2.0% after the Facebook parent said it is testing a monthly subscription service called Meta Verified, which will let users verify their accounts using a government ID and get a blue badge.

A trader works on the floor of the New York Stock Exchange (NYSE) in New York City, U.S., February 17, 2023. REUTERS/Brendan McDermid

Wisconsin voters on Tuesday will decide which state Supreme Court candidates will advance to an April election that carries profound consequences for abortion rights, control of the state government and the 2024 presidential election.

Four candidates – two liberals and two conservatives – are on the ballot, with the top two finishers moving on to a one-on-one matchup in April that will determine whether a right-wing or left-wing majority controls the state's seven-member high court.

The newly constituted court will likely decide whether to uphold the state's 1849 near-total abortion ban that took effect after the U.S. Supreme Court's decision last June to overturn Roe v. Wade, eliminating a national right to abortion.

The court may also reexamine the state's Republican-drawn legislative maps, which have helped the party maintain dominance over the legislature despite a closely divided electorate. And the justices could issue election law rulings that affect the outcome of the 2024 presidential race, when Wisconsin is expected to be a swing state.

"The stakes in this race for Wisconsin and for American democracy at large can't be overstated," Ben Wikler, the chair of the state's Democratic Party, said in an interview.

With a Democratic governor, Tony Evers, and a Republican-majority legislature often at loggerheads, the state Supreme Court's 4-3 conservative majority has issued a string of decisions that typically favored Republicans.

But a conservative justice is leaving the bench this year, putting the political leaning of the court in question.

While the race is technically nonpartisan, a casual observer would be forgiven for missing that detail. The candidates – liberals Janet Protasiewicz and Everett Mitchell and conservatives Daniel Kelly and Jennifer Dorow – have left little doubt about their ideological tendencies.

Both the state Democratic and Republican parties have lined up behind each pair of like-minded candidates, while a constellation of interest groups have issued endorsements and poured millions of dollars into the campaigns.

The contest already ranks among the most expensive state supreme court races in history, according to Douglas Keith, an attorney at New York University's Brennan Center for Justice who tracks spending on judicial elections.

More than $7 million has been spent on television advertising with six weeks before the general election, putting it on track to shatter the $15 million overall spending record for a single-seat race, set in 2004 in Illinois.

State judicial elections have received greater attention in recent years, a trend accelerated by the Supreme Court's decision to overturn Roe v. Wade.

In Wisconsin, the ruling triggered the 19th-century law banning the procedure. Democratic Attorney General Josh Kaul filed a lawsuit claiming the statute is invalid - a case eventually headed for the state Supreme Court.

"This is Wisconsin's Roe moment," said Gracie Skogman, a spokesperson for Wisconsin Right to Life, which is backing the conservative candidates. "It's not only the fate of our current law that is in jeopardy depending on the ideological makeup of the court, but they have the opportunity to set the standard for pro-life and abortion policy for decades to come."

Right to Life is mobilizing voters with direct mail, phone calls, social media appeals and a voter registration drive.

Planned Parenthood Advocates of Wisconsin plans to invest more resources in the campaign than any previous judicial race, spokesperson Tiffany Wynn said. The group has hired staff to canvass door-to-door and is planning an advertising blitz after Tuesday's primary.

A new liberal majority could also revisit other statutes, such as laws requiring voter identification and permitting concealed carry of firearms.

"These are issues right up and down the line that we've been tackling over the last generation that would be on the chopping block," said Mark Jefferson, the Republican state party chair.

Wisconsin Supreme Court Justice Daniel Kelly speaks at a leadership training session for local Republican Party officials and volunteers in Waukesha, Wisconsin, U.S., September 7, 2019. Picture taken September 7, 2019. REUTERS/Brian Snyder/File Photo

Voters in Virginia's fourth U.S. House of Representatives district go to the polls on Tuesday for a special election in which Democratic state Senator Jennifer McClellan is favored to win, a victory that would make her the first Black congresswoman from the state.

"It blows my mind that we're still having firsts in 2023, but I'm very honored," she told ABC News last week.

The special election is to fill a vacancy created by the November death of Representative Don McEachin , a Democrat who won re-election to what would have been a fourth term by a 65%-35% margin over Republican challenger Leon Benjamin.

McClellan is a former corporate lawyer for whom McEachin was a mentor. A victory for his seat by the Democrat would restore the narrow margin Republicans had claimed after the November midterms.

Her main issues in Congress would be cost of living, affordable healthcare and voting rights, she said.

Benjamin, a supporter of former President Donald Trump, is running against her. The race is Benjamin's third attempt to capture the district, after refusing to concede in 2020 and 2022.

"Not to be cliche, but third time's the charm," he told news outlet Axios last week.

The district stretches from the capital of Richmond to the state's southern border, and is considered safely Democratic by analysts.

A McClellan win would leave Republican House Speaker Kevin McCarthy with a nine-seat majority, 222-213.

Polls close at 7 p.m. EST (2400 GMT) on Tuesday.

McEachin died after battling cancer on Nov. 28, less than three weeks after the Nov. 8 elections, before the new Congress was sworn in on Jan. 3.

British companies trialling a four-day working week have mostly decided to stick with it after a six-month pilot in what campaigners for better work-life balance view as a breakthrough.

Employees at 61 companies across Britain worked an average of 34 hours across four days between June and December 2022, while earning their existing salary.

Of those, 56 companies, or 92%, opted to continue like that, 18 of them permanently.

The trial is the largest in the world to date , according to Autonomy, a British-based research organisation which published the report alongside a group of academics and with backing from New Zealand-based group 4 Day Week Global.

Most companies involved, across different sectors and sizes with 2,900 staff overall, said productivity was maintained.

Staff said their well-being and work-life balance had improved while data showed employees were much less likely to quit their jobs as a result of the four-day week policy.

"This is a major breakthrough moment for the movement towards a four-day working week," Joe Ryle, Director of the 4 Day Week Campaign, said in a statement on Tuesday.

"These incredible results show that the four-day week with no loss of pay really works."

The founder of a craft brewery involved in the trial said the trial encouraged greater productivity in shorter time. "We want to be more busy, less stressed," the report quoted the founder as saying.

For some employees surveyed, the extra day off was more important than any pay rise: 15% said no amount of money would induce them back to a five-day week.

Companies from the marketing and advertising, professional services and charity sectors were most represented in the trial. Some 66% of those participating had 25 or fewer employees, while 22% had 50 or more staff.

Which four days employees worked varied. Some staff had Wednesdays off, while others had a three-day weekend policy.

The trial's evidence that a four-day week helps retain staff could prove powerful in Britain, where there is a labour shortage since departure from the European Union and the COVID pandemic.

"That should give us a competitive advantage," a senior manager at an insurance firm in the trial said of four-day weeks.

A man works at a computer on a standing desk in an office in the financial district of Canary Wharf in London, Britain, February 8, 2023. REUTERS/Kevin Coombs

An Iranian foundation has praised the man who attacked novelist Salman Rushdie last year, leaving him severely injured, and said it will reward him with 1,000 square metres of agricultural land, state TV reported on Tuesday through its Telegram channel.

Rushdie, 75, lost an eye and the use of one hand following the assault by a 24-year-old Shi'ite Muslim American from New Jersey on the stage of a literary event held near Lake Erie in western New York in August. read more

"We sincerely thank the brave action of the young American who made Muslims happy by blinding one of Rushdie's eyes and disabling one of his hands," said Mohammad Esmail Zarei, secretary of the Foundation to Implement Imam Khomeini's Fatwas.

"Rushdie is now no more than living dead and to honour this brave action, about 1,000 square metres of agricultural land will be donated to the person or any of his legal representatives," Zarei added.

The attack came 33 years after Ayatollah Ruhollah Khomeini, then Iran's supreme leader, issued a fatwa, or religious edict, calling on Muslims to assassinate Rushdie a few months after "The Satanic Verses" was published. Some Muslims saw passages in the novel about the Prophet Muhammad as blasphemous.

Rushdie, who was born in India to a Muslim Kashmiri family, has lived with a bounty on his head, and spent nine years in hiding under British police protection.

While Iran's pro-reform government of President Mohammad Khatami distanced itself from the fatwa in the late 1990s, the multimillion-dollar bounty hanging over Rushdie's head kept growing and the fatwa was never lifted.

Khomeini's successor, Supreme Leader Ayatollah Ali Khamenei, was suspended from Twitter in 2019 for saying the fatwa against Rushdie was "irrevocable."

The man accused of attacking the novelist has pleaded not guilty to second-degree attempted murder and assault charges.

A downturn in South Korea's home prices is causing pain in the country's unusual rent-free rental system that benefited landlords and tenants alike during a long surge in residential property prices.

In the "jeonse" scheme, tenants put up a deposit typically worth as much as 70% of the home's value, then live without paying rent for two years until the landlord returns the full amount.

This was a win-win for residents and owners for years as home prices rose and interest rates were high: the loan tenants paid to raise their deposit was cheaper than rent and landlords got an interest-free loan to deploy as they pleased.

Jeonse tenancy has been particularly popular among people in their 20s and 30s, who could not afford the full price of a home but could use the system to get a toehold into the Korean dream of home ownership.

But median house prices have fallen 12% and jeonse prices 7% over the two years to January after surging 37% and 24%, respectively, over the preceding four years, according to Korea Real Estate Board data.

Overextended landlords are failing to return deposits, hitting younger tenants especially hard and threatening to undermine trust in the system.

Yoo Ha-jin, 28, regrets not getting insurance for her jeonse deposit when she signed in March 2021. Her bankrupt landlord told her in December the property would be auctioned and she could expect to get around 45% of her deposit back at most.

That means she will owe at least 33 million won ($25,000) for the loan she took out on her jeonse contract expiring next month.

"I thought I would be just fine as long as I could get a jeonse deposit loan from the bank," Yoo told Reuters.

Insurance claims for failed jeonse repayments more than doubled last year to a record 1.17 trillion won ($903 million), according to Korea Housing and Urban Guarantee Corp, one of the country's three major guarantors.

Tenants in their 20s and 30s accounted for 70% of the total.

Financial authorities are working closely with other agencies to support jeonse tenants and landlords having difficulty with refunds, said an official at the Financial Services Commission.

Police are cracking down on jeonse-related crimes, saying organised fraud cases more than tripled last year to 622.

Jeonse deposit loans more than quadrupled in less than six years through October to 172 trillion won ($132 billion), according to the central bank. That equals 17% of South Korea's outstanding mortgages and 10% of household debt.

Still, almost all jeonse loans have guarantees from public enterprises, leaving little credit risk for commercial lenders.

"The jeonse crisis poses limited macroeconomic risks, yet it is still another part of the whole property market fallout," said economist Moon Hong-cheol at DB Financial Investment.

Unexpected debt burdens on young people could exacerbate risks for the property market, a key sector that drives growth and affects financial markets. Fears of defaults on real estate projects last year triggered a credit crunch in South Korea's financial markets.

Some investment banks, such as Nomura and Citi, predict the Bank of Korea will start cutting interest rates as soon as the next three to six months to engineer a soft landing for the property market.

"It is frustrating there is really no one to blame," said Yoo, the stranded jeonse tenant. "I just think maybe I could have avoided this kind of trouble, had I had enough money to purchase my own house."

($1 = 1,295.8700 won)

Yoo Ha-jin, 27, looks at a building where she lives in Seoul, South Korea, February 21, 2023. REUTERS/Kim Hong-Ji Yoo Ha-jin, 27, looks at a building where she lives in Seoul, South Korea, February 21, 2023. REUTERS/Kim Hong-Ji

A look at the day ahead in European and global markets from Ankur Banerjee:

After a sputtering start to the week for the equities market, flash PMI data from Eurozone, UK and Germany will likely give some sort of direction for traders. Investors have put on their risk-off hats so far, with the dollar ascendant on Tuesday, having erased its year to date losses and as Asian equities flirt with six-week lows.

With U.S. markets set to reopen after Monday's holiday, investor focus will be squarely on minutes from the Feb. 1 Federal Reserve meeting, scheduled to be released on Wednesday.

At that meeting, the central bank raised interest rates by 25 basis points and said disinflation was underway. Resilient economic data for the past month has brought back investor fears that the Fed will have to hike more and stay higher for longer.

Minutes from the Reserve Bank of Australia's policy meeting in February showed the board abandoned all thought of pausing rate hikes in the face of sticky inflation and signalled more hikes would be needed in the months ahead.

Meanwhile, Russian President Vladimir Putin was due to make a speech on Tuesday setting out aims for the second year of his invasion of Ukraine. It comes just a day after U.S. President Joe Biden's surprise visit to Ukraine where he walked the streets of Kyiv and promised to stand with Ukraine as long as it takes.

In the corporate world, global miner BHP Group (BHP.AX) reported a dour first half earnings but pinned hopes on a rebound in demand from China, its biggest customer.

Europe's largest bank HSBC Holdings (HSBA.L) unveiled plans for a special dividend and share buybacks as rising interest rates swelled net interest income.

Earnings from Walmart (WMT.N) later in the day will shed light on American consumers' buying habits in the face of rising expenses.

Key developments that could influence markets on Tuesday:

Economic events: Flash PMIs for Germany, France, UK and Eurozone

A trader works at Frankfurt's stock exchange in Frankfurt, Germany, March 12, 2020. REUTERS/Ralph Orlowski