Biden says 'butcher' Putin 'cannot remain in power'

US President Joe Biden on Saturday castigated Vladimir Putin over the month-old war in Ukraine, bluntly calling the Russian leader "a butcher" who "cannot remain in power".

In an impassioned speech from the Royal Castle in Warsaw, delivered after meeting top Ukrainian ministers in Poland and earlier conferring with NATO and EU allies on the conflict, Biden plainly warned Russia: "Don't even think about moving on one single inch of NATO territory."

Although the White House moved quickly to temper Biden's unprecedented comments on Putin -- insisting the US leader is not seeking "regime change" in Russia and was referring to Putin's influence over neighbours in the region -- the Kremlin made its displeasure clear.

Personal attacks, one official said, were "narrowing down the window of opportunity" for bilateral relations.

Biden coupled his harsh words for Putin with a pointed attempt to appeal to ordinary Russians, saying they were "not our enemy" and urging them to blame their president for the heavy sanctions imposed by the West.

He offered reassurance to Ukrainians in the audience and elsewhere, at a time when nearly four million of them have been driven out of their country. "We stand with you," he said.

Biden also cast doubt on Russia's signal that it may scale down its war aims to concentrate on eastern Ukraine -- even as two Russian missile strikes slammed into the west of the country.

The president said he was "not sure" Moscow has indeed changed its objectives, which, so far, he said had resulted in "strategic failure".

Two Russian missiles earlier struck a fuel depot in western Ukraine's Lviv, a rare attack on a city just 70 kilometres (45 miles) from the Polish border, which has escaped serious fighting.

At least five people were wounded, regional governor Maksym Kozytsky said, as AFP journalists in the city centre saw plumes of thick black smoke.

Putin sent troops into Ukraine on February 24, vowing to destroy the country's military and topple pro-Western President Volodymyr Zelensky.

But his army has made little progress on capturing key cities, and it has hit hospitals, residential buildings and schools in increasingly deadly attacks on civilians.

Biden, who was winding up a whirlwind visit to Poland after holding a series of urgent summits in Brussels with Western allies, earlier met Ukraine's Foreign Minister Dmytro Kuleba and Defence Minister Oleksii Reznikov in Warsaw in an emphatic show of support for Kyiv.

Both ministers had made a rare trip out of Ukraine for the face-to-face talks, in a potential sign of growing confidence in their battle against Russian forces.

In a possible shift on a plan to transfer Soviet-era fighter jets from Poland to Kyiv to boost Ukraine's firepower in the skies -- rejected last month by the Pentagon as too "high risk" -- Kuleba said the United States now did not object.

"As far as we can conclude, the ball is now on the Polish side," Kuleba said in written comments to AFP after the meeting.

In a video address, Zelensky reiterated a call for planes while urging allies to supply Ukraine with more weapons.

"We need more ammunition. We need it to protect not only Ukraine but other Eastern European countries that Russia threatened to invade," he said.

"During the meeting... with our American colleagues in Poland we made it clear again," he said.

"What is NATO is doing? Is it being run by Russia? What are they waiting for? It's been 31 days. We are only asking for one percent of what NATO has, nothing more."

US Secretary of State Antony Blinken, meanwhile, announced an additional $100 million in aid to help Ukraine police and border guards purchase armoured vehicles, equipment and medical supplies, a statement said.

KF/