A scathing comment made by US President Joe Biden has been deemed "unforgivable" by Russian President Vladimir Putin.
On Wednesday, Biden was asked by a journalist whether he believed Putin to be a "war criminal"
"I think he is a war criminal," he said in an off-the-cuff comment to a group of reporters before being escorted away.
It is the sharpest condemnation yet of Putin and Russian actions by a US official since the invasion of Ukraine.
The brief exchange came after Ukrainian President Volodymyr Zelensky addressed the US Congress.
Biden's official Twitter account also called out Putin for "inflicting devastation" on Ukraine.
"Putin is inflicting appalling devastation and horror on Ukraine — bombing apartment buildings and maternity wards," the account managed by the Biden administration said.
"Yesterday, we saw reports that Russian forces were holding hundreds of doctors and patients hostage. These are atrocities. It is an outrage to the world."
Putin is inflicting appalling devastation and horror on Ukraine — bombing apartment buildings and maternity wards.
Yesterday, we saw reports that Russian forces were holding hundreds of doctors and patients hostage.
These are atrocities. It is an outrage to the world.
— President Biden (@POTUS) March 16, 2022
Now, Putin's spokesperson Dmitry Peskov has responded to Biden's remarks, saying the assertion that Russia's president is a war criminal was "unforgivable".
"We believe such rhetoric to be unacceptable and unforgivable on the part of the head of a state, whose bombs have killed hundreds of thousands of people around the world," Peskov reportedly said, stopping short of calling the US President a hypocrite.
Russia's invasion of Ukraine sparked international outrage, and while other world leaders have labelled Putin a "war criminal", the White House has been hesitant to declare Putin as such because it was a legal term that required research.
White House press secretary Jen Psaki said the president was “speaking from his heart” with his comments and renewed her statements that there is a process for making a formal determination.
While Russian forces have so far failed to capture any of Ukraine's biggest cities, the assault has been the largest on a European state since World War II.
Bomb dropped on theatre housing civilians
Ukraine's foreign ministry said Russian forces dropped a powerful bomb on a theatre in Mariupol, a besieged port city in southern Ukraine.
There is an unknown number of casualties, though Human Rights Watch said the theatre had been housing at least 500 civilians.
Maxar Technologies, a private US company, distributed a satellite image from March 14 which showed the word "children" in Russian had been painted on the ground near the building.
Biden has pledged more aid to help Ukraine fight Russia.
What is a war criminal?
The term applies to anyone who violates a set of rules adopted by world leaders known as the law of armed conflict, the Associated Press explained.
The rules govern how countries behave in times of war.
Those rules have been modified and expanded over the past century, drawn from the Geneva Conventions in the aftermath of World War II and protocols added later.
The rules are meant to protect those who are not taking part in the fighting, or can no longer fight, including civilians like doctors and nurses, wounded troops and prisoners of war.
There are treaties and protocols which lay out who can be targeted and with what weapons.
Certain weapons are prohibited, including chemical or biological agents.
With AP and Reuters
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