Two Republican U.S. lawmakers, including the only Ukrainian-American in Congress, on Wednesday announced a resolution calling for Russian President Vladimir Putin to be investigated for war crimes and crimes against humanity.

U.S. Representative Victoria Spartz, the only Ukrainian-American in Congress, and Senator Lindsey Graham held a news conference on their resolution amid debate in the U.S. Congress about how best to support Ukraine, including plans to approve billions of dollars in humanitarian and military aid for the Kyiv government in the wake of the Russian invasion.

The resolution supports Ukraine's war crimes complaint to the International Criminal Court and urges the ICC and the International Court of Justice to expand their investigations to include Russian commanders who might be carrying out war crimes.

"This is real bad for all of us and I hope these people can survive," Spartz said, after reading chilling messages she had received from Ukraine about attacks that have injured civilians, forcing them to flee for their lives.

The office of the prosecutor of the International Criminal Court said on Monday it would seek court approval to open an investigation into alleged war crimes in Ukraine.

Since Russia invaded Ukraine on Feb. 24, rights groups have alleged violations of international war crimes law, including the targeting of civilians, as well as indiscriminate attacks on schools and hospitals.

British Prime Minister Boris Johnson said on Wednesday that he believed Putin's actions toward Ukraine already qualified as a war crime. And Canada said on Tuesday it had decided to refer the situation in Ukraine to the International Criminal Court.