The fresh attacks came amid renewed efforts at meetings in Geneva to secure a US-led peace deal acceptable to both Russia and Ukraine, despite Vladimir Putin showing no sign he wants the war to end.

From the front-line city of Pokrovsk in eastern Donetsk, to Zaporizhzhia in the south, there is little doubt that Russia is making advances. But, battlefield monitors suggest the picture is not quite so bleak for Ukraine as Trump and Putin suggest.

NATO Secretary-General Mark Rutte says a US peace proposal has helped bring Kyiv and Washington closer together on the way toward ending the war between Russia and Ukraine, Europe's biggest and deadliest conflict since World War II.

Russian President Vladimir Putin on Monday said the current US peace proposal that heavily favors Moscow could “form the basis for a final peace settlement” in Ukraine.

Sen. Mitch McConnell, a staunch supporter of Ukraine, has warned the proposal to end the war with Russia could come with consequences.

While President Trump attacked the Ukrainians, Secretary of State Marco Rubio flew to Geneva to seize control of negotiations that were going off the rails.

Poland's armed forces have scrambled fighter jets and placed air defences on "maximum readiness" as fears grow that Russia is preparing for war against NATO.