US President Joe Biden has accused Russian forces of committing acts of “genocide” in Ukraine.
He said Russian President Vladimir Putin was trying to “wipe out the idea” of a Ukrainian identity.
Mr Biden has previously stopped short of references to genocide, instead accusing Moscow of “war crimes”.
French President Emmanuel Macron later told French TV he was reluctant to use the term and warned against an “escalation of rhetoric”.
Speaking to the public broadcaster France 2, the French President said he would be “careful with such terms today because these two peoples are brothers.”
“I want to continue to try, as much as I can, to stop this war and rebuild peace. I am not sure that an escalation of rhetoric serves that cause,” he added.
But Mr Biden insisted on Tuesday night that evidence of genocidal acts by Russian troops was mounting.
“More evidence is coming out of the horrible things that the Russians have done in Ukraine,” the president said. “And we’re going to only learn more and more about the devastation. We’ll let the lawyers decide internationally whether or not it qualifies, but it sure seems that way to me.”
He first made the comments as part of a throwaway remark during a speech in Iowa about increasing inflation, telling supporters in Iowa their ability to budget should not “hinge on whether a dictator declares war and commits genocide half a world away”.
Ukrainian President Volodymyr Zelensky, who has not held back from accusing Russia of genocide and “crimes against humanity” following the discovery of mass graves in the city of Bucha, said Mr Biden’s comments were “true words of a true leader”.
“Calling things by their names is essential to stand up to evil,” Mr Zelensky wrote on Twitter.
The White House posted a copy of Mr Biden’s comments online.
Last month, US officials rowed back on comments President Biden made in Warsaw. At the end of a speech in front of Polish government officials and dignitaries he said of Mr Putin: “For God’s sake, this man cannot remain in power.”
The US quickly issued a clarification amid fierce backlash from the Kremlin. “The president’s point was that Putin cannot be allowed to exercise power over his neighbours or the region,” a Biden administration official said. “He was not discussing Putin’s power in Russia, or regime change.”
Genocide is widely seen as the most serious crime against humanity and is defined under international law as a mass extermination of a particular group of people.
While there is no legal consensus on whether Russia is guilty of the crime, Poland’s Prime Minister Mateusz Morawiecki has described killings in the town of Bucha as “acts of genocide”. And last week, UK Prime Minister Boris Johnson said the attacks do not “look far short of genocide”.