Canadian Prime Minister Justin Trudeau said it was "right" to describe Russia's attacks in Ukraine as "genocide," repeating US President Joe Biden's accusation.
"I think it's absolutely right that more and more people be talking and using the word genocide in terms of what Russia is doing, what Vladimir Putin has done," Trudeau told reporters in Quebec, making him one of the first world leaders to use the term.
"We have seen this desire to attack civilians, to use sexual violence as a weapon of war," he said. "This is completely unacceptable."
Mr Trudeau added that Canada was one of the first countries to initiate a process at the International Criminal Court to hold Russia's leader accountable for his "war crimes."
Mr Biden on Tuesday accused Putin of genocide, while giving a speech about gasoline prices.
"Your family budget, your ability to fill up your tank - none of it should hinge on whether a dictator declares war and commits genocide half a world away," Biden said at the event in Iowa.
The Biden administration has sought to blame sharp rises at US gas stations on Putin's invasion of neighboring Ukraine, during which Russian troops have been accused of committing atrocities against civilians.
Mr Biden said it would ultimately be up to courts to determine whether Russia's actions in its ex-Soviet neighbor constitute genocide.
But "the evidence is mounting," he added.
British Prime Minister Boris Johnson also said last week that the alleged massacre in Bucha "doesn't look far short of genocide to me."
Ukraine has been accusing Russia of committing war crimes and genocide since even before the discovery of hundreds of civilians reportedly killed in Bucha, which sparked an outpouring of revulsion.
But western countries have stopped short of using the term "genocide," in line with longstanding protocol, because of its strict legal definition and the heavy implication the accusation carries.
The French and German leaders acknowledged Wednesday Russia had committed war crimes but declined to repeat Biden's accusation, warning that verbal escalations would not help end the war.