Emergency workers collect dead bodies in Mariupol

STORY: However, hundreds of fighters and civilians were still holed up inside a huge steelworks and Ukraine said Putin wanted to avoid a final clash with its forces in the city as he lacked the troops to defeat them.

Reuters footage from the devastated port city showed bodies being collected by men in white hazmat suits and being placed into the back of vehicles marked with the letter 'Z'. It was unclear where the bodies were being taken.

Mariupol, once home to 400,000 people, has seen not only the most intense battle of the war that started when Russian forces invaded on Feb. 24, but also its worst humanitarian catastrophe.

Hundreds of thousands of civilians have been cut off for nearly two months under Russian siege and bombardment.