Ukraine's Prime Minister Denys Shmyhal called the situation in Mariupol the "biggest humanitarian catastrophe" since Russia's invasion -- and perhaps the worst catastrophe of the century, as the southeastern port city faces constant bombardment from Russian forces.
Speaking at a press conference in Washington on Friday, Shmyhal said thousands of people had died in Mariupol, adding: "We will see the terrible atrocities when it will be liberated from Russians."
He said Russian troops are "absolutely destroying everything," including shelters where civilians are staying.
An estimated 100,000 people remain trapped in Mariupol since it was surrounded by Russian forces on March 1, according to Ukrainian officials. Ukrainian officials claim that more than 20,000 people in the city have died during the assault.
CNN cannot independently identify these figures, as a firm death toll following weeks of heavy bombardment is not available.
The last holdout of resistance: On Friday, Shmyhal said civilians including women and children are hiding at the Azovstal steel plant, the final bastion of Ukrainian defenders inside the city. He said the Russian army is still surrounding the area, and Ukraine is speaking with partners to negotiate an evacuation corridor.
He also called on ambassadors from all countries, including the United States, to return to their embassies in Kyiv.