(Reuters) - U.S. President Joe Biden made an unannounced visit to Kyiv on Monday in a show of support ahead of the one-year anniversary of Russia's invasion, promising President Volodymyr Zelenskiy that Washington would stand with Ukraine as long as it takes.
Air raid sirens blared across the Ukrainian capital as Biden visited Kyiv, although there were no reports of Russian missile or air strikes.
"Your visit is an extremely important sign of support for all Ukrainians," Zelenskiy said, adding that he and Biden discussed long range weapons during the visit.
The White House said Biden would announce more sanctions on Russia and military support for Ukraine including artillery ammunition, anti-armour systems and air surveillance radars.
Biden's visit came a day before President Vladimir Putin was due to make a major address, expected to set out Russia's aims for the second year of the invasion he launched on Feb. 24 last year.
The anniversary has taken on more than symbolic significance, becoming what the West views as motivation for the war's deadliest phase as Moscow hurls thousands of conscripts and mercenaries into a winter offensive.
Russia has secured only scant gains so far in assaults in frozen trenches up and down the eastern front in recent weeks. Kyiv and the West see it as a push to give Putin victories to tout a year after he launched Europe's biggest war since World War Two.
Moscow received its own apparent signal of diplomatic support, with Chinese foreign minister Wang Yi expected in the Russian capital for talks. In public, China has so far remained neutral over the conflict despite signing a "no limits" friendship pact with Russia weeks before the invasion.