Sen. Chuck Grassley, R-Iowa, labeled Russian President Vladimir Putin the "Butcher of Bucha" on Tuesday.
His comments came in a tweet where he compared Putin to the Gestapo's Klaus Barbie, who was called the "Butcher of Lyon" for his atrocities in World War II.
Grassley wrote: "Putin now earns title of 'Butcher of Bucha' for execution of civilians. Just like Klaus Barbie was the Butcher of Lyon in WWII."
President Joe Biden, citing reported atrocities in Ukraine, has called for a war crimes trial against Putin, The Associated Press reported.
"You saw what happened in Bucha," Biden said, adding that Putin "is a war criminal. What's happening in Bucha is outrageous, and everyone sees it."
Biden's remarks came after Ukraine President Volodymyr Zelenskyy visited Bucha, a town outside of Kyiv, where Ukrainian officials say the bodies of civilians have been discovered, according to AP.
Zelenskyy said the Russian actions were "genocide."