President Biden on Wednesday was asked by reporters whether he was ready to call Russian President Putin a war criminal.

"I think he is a war criminal," Biden said.

White House press secretary Jen Psaki noted that a legal review has been under way at the State Department to review the matter.

"He was speaking from his heart," she said.

This is the furthest that Biden — who often emphasizes the role of personal leader-to-leader diplomacy in international relations — has gone to decry the actions taken by Putin. When asked earlier this month if he thought Russia was committing war crimes, he said the White House was following events closely but that "It's too early to say that."

Biden spoke earlier in the day about 'atrocities' in Ukraine

Earlier Wednesday Biden spoke about the "appalling devastation" inflicted on Ukraine, including reports of doctors and patients being held hostage in Mariopol. "These are atrocities," Biden said. "It's an outrage to the world."

The White House has called for an investigation into if Russian forces are committing war crimes in Ukraine, and experts have told NPR that evidence of them is "undoubtable." If any International Criminal Court investigation advances, Putin and his generals could face indictment.

Last week, Vice President Harris and Polish President Andrzej Duda decried Russia for its attacks on Ukrainian hospitals. Harris said the world had witnessed "atrocities of unimaginable proportion" with the attacks, and said the United States and Poland were unified "in partnership and solidarity" to support Ukraine's humanitarian and security needs. Duda spoke about the "barbarous aggression" from Russia, saying it had "the features of a genocide," noting particularly the bombing of a maternity hospital in Ukraine.

"It is obvious to us that, in Ukraine, Russians are committing war crimes," Duda said. Harris expressed support for the ongoing war crimes investigation. "Absolutely there should be an investigation, and we should all be watching," she said.

Copyright 2022 NPR. To see more, visit https://www.npr.org.