Top EU diplomat accuses Russia of 'massive war crime' in Mariupol assault

The European Union's top diplomat is accusing Russia of "a massive war crime" in Moscow's assault against the Ukrainian city of Mariupol.

"This is a war crime, a massive war crime, what's happening in Mariupol," Josep Borrell, the EU's foreign policy chief, told reporters on Monday. "The city will be completely destroyed, and people will be - are dying."

Mariupol has come under attack by Russian forces throughout Moscow's invasion of Ukraine, which began late last month. On Monday, the Mariupol City Council claimed that Russia bombed an art school in the city where hundreds of refugees were sheltering.

One day before that, the Mariupol City Council said thousands of residents had been forcibly taken to Russian territory.

The offensive in Mariupol reached an apex on Sunday, when Russia called on Ukrainians to lay down their arms and end what it labeled a "terrible humanitarian catastrophe" in the city.

Officials there, however, rejected the plea on Monday. Ukrainian Deputy Prime Minister Iryna Vereshchuk said "there can be no question of any surrender, laying down of arms."

"We have already informed the Russian side about this," Vereshchuk added.

Human Rights Watch is calling on the International Criminal Court, the United Nations Human Rights Council's Commission of Inquiry and other relevant authorities to "investigate potential war crimes in Mariupol, with a view to prosecuting those most responsible," according to a new report from the group out on Monday.

An International Criminal Court prosecutor earlier this month launched an investigation into "allegations of war crimes, crimes against humanity or genocide committed on any part of the territory of Ukraine by any person."

President Biden last week called Russian President Vladimir Putin a "war criminal." One day later, Secretary of State Antony Blinken said he views Russia's offensives in Ukraine as war crimes, telling reporters that he agrees with Biden's assessment.