Biden calls Putin “war criminal,” in first

"I think he is a war criminal," Biden responded, according to CNN.

White House press secretary Jen Psaki said the State Department was yet to review the matter in a legal review.

"He was speaking from his heart," Psaki 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," NPR reported.

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