US President Joe Biden is expected to lay out his view of the war in Ukraine as a battle for democracy during a speech later on Monday.
He will make his address in the Polish capital, Warsaw, as part of his three-day visit to the country.
It will come hours after Russia’s president accused the West of being responsible for the war.
On Monday, Mr Biden made a surprise visit to Ukraine to reaffirm America’s support for Kyiv.
The competing speeches by both leaders come days before the first anniversary of Russia’s full-scale invasion of Ukraine.
In Warsaw, the US president is expected to stress the vital role the United States has played in galvanising western backing for Ukraine against Russian aggression.
But he will also be looking to shore up support for his policy at home, where some politicians are expressing doubts about the scale of US involvement.
Earlier on Tuesday, Russian President Vladimir Putin made his annual state of the nation speech – accusing the West of hypocrisy and of withdrawing from “fundamental agreements”.
“I want to repeat: it is them who are culpable for the war, and we are using force to stop it,” he said to great applause.
Mr Putin also reiterated his unfounded claim that Moscow had been facing a Nazi threat from Ukraine, which he used as justification to launch his “special military operation”.
Ahead of his address, US President Joe Biden will meet Poland’s leader, Andrzej Duda, and other central European allies to discuss bilateral cooperation and to strengthen Nato against aggression.
That’s after the president met his Ukrainian counterpart, Volodymyr Zelensky, in Kyiv on Monday – telling a press conference that the US will back Ukraine for “as long as it takes”.
“We have every confidence you’re going to continue to prevail,” he said.
The pair also visited a memorial to soldiers who have died in the nine years since Russia annexed Crimea and its proxy forces captured parts of the eastern Donbas region.
After the visit, US Secretary of State Antony Blinken announced a new package of security assistance for Ukraine valued at $450m (£373m), as well as an extra $10m in emergency assistance to maintain Ukraine’s energy infrastructure.
A new wave of sanctions against individuals and companies “that are trying to evade or backfill Russia’s war machine” will also be announced later this week.
The US is one of Ukraine’s biggest allies and has already given billions of dollars in military assistance.
Mr Biden recently announced that the US would send 31 battle tanks and longer-range missiles but has stopped short so far of sending F-16 fighter jets, despite repeated calls for them from Ukraine.
However, Mr Zelensky on Monday said that he had discussed with Joe Biden the possibility of the US sending other weapons.
