Poland's prime minister rebuked French President Emmanuel Macron for negotiating with Russian leader Vladimir Putin, whom he likened to Adolf Hitler and Joseph Stalin.
Putin and Moscow are facing vehement criticism from Western leaders after Ukraine accused Russian forces of committing a "genocide" and "war crimes" in the city of Bucha.
Russia has rejected the allegations as a "fake news attack," arguing that images of dead bodies and footage of slain civilians that have drawn global outrage were staged after Russian forces withdrew from the city.
"Mr. President Macron, how many times have you negotiated with Putin, what have you achieved? Have you stopped any of the actions that have taken place?" Polish Prime Minister Mateusz Morawiecki said at a press conference on Monday.
"One should not negotiate with criminals, one should fight them ... Nobody negotiated with Hitler. Would you negotiate with Hitler, Stalin, Pol Pot?" he added.
Macron has had at least 17 phone calls and a meeting in Moscow with Putin since last December, first in a bid to prevent conflict in Ukraine and now to broker peace between the two sides.
The French leader also distanced himself from U.S. President Joe Biden's comment in which he called Putin a "butcher."
"I will not use this kind of remark because I continue to talk with President Putin," Macron told a local news channel a day after Biden made the comment in Poland on March 26.
He also warned against an escalation of words and actions in Ukraine, where the civilian death toll since Feb. 24 now stands at 1,430 and another 2,097 have been injured, according to UN estimates, with the true figure feared to be far higher.
More than 4.21 million Ukrainians have also fled to other countries, with millions more internally displaced, according to the UN refugee agency.