The Kremlin said Wednesday it was "unacceptable" for US President Joe Biden to accuse Moscow's troops of committing genocide in Ukraine, where Russia has been conducting a military campaign for nearly two months.

"We categorically disagree and consider unacceptable any attempt to distort the situation in this way, especially since it is hardly acceptable for the president of the United States," Kremlin spokesman Dmitry Peskov told reporters.

He added that the United States is a "country that has committed well-known deeds in modern and recent history". 

Biden on Tuesday accused President Vladimir Putin's forces of committing genocide in Ukraine, the first time his administration has used the term. 

Biden said it would ultimately be up to courts to determine whether Russia's actions in its pro-Western neighbour -- where it stands accused of atrocities against civilians -- constitute genocide.