President Joe Biden Monday joined calls to prosecute Russian President Vladimir Putin for war crimes in Ukraine. Speaking to reporters, Biden acknowledged that he faced criticism for calling Putin a war criminal, but he stood by his statement. He specifically pointed to Russian action in Bucha, a suburb of Kyiv. Biden announced his intention to seek a “wartime trial” and prosecute Putin as a war criminal but did not give further details on the matter.

The United Nations Office of the High Commissioner for Human Rights has reported 3,455 civilian casualties since Russia invaded Ukraine on February 24, including 1,417 civilians deaths. The Commissioner, Michelle Bachelet, said she was “horrified by the images of civilians lying dead on the streets” in Bucha. Bachelet called for independent and “effective” investigations of events in Bucha.

UN Secretary-General António Guterres said he was “deeply shocked” by images of the destruction of Bucha. Guterres said, “[i]t is essential that an independent investigation leads to effective accountability.” 

Human Rights Watch (HRW) Sunday released a report detailing recent Russian atrocities in Ukraine. Investigators heard firsthand reports of civilian executions, rape and looting of civilian resources. One Ukrainian woman told HRW that “Russian forces in the village of Staryi Bykiv, in Chernihiv region, rounded up at least six men on February 27, and later executed them.” Another witness told HRW that Russian soldiers forced “five men to kneel on the side of the road, pulled their T-shirts over their heads, and shot one of the men in the back of the head.”

Under customary international law and treaties like the Geneva Conventions, anyone who “orders or deliberately commits” or aids and abets acts like rape, torture, looting and willful killing of prisoners or civilians is guilty of a war crime.