Mariupol Mayor Vadym Boychenko told AP during an interview Monday that at least 10,000 civilians died during Russia's siege of the port city that started in early March and warned that the death toll could pass 20,000.

The big picture: The city, once home to almost 500,000 people, has been utterly devastated after weeks of Russian military bombardment, and Ukrainian officials fear there are still thousands of civilians trapped in the city with food, water and medicine in short supply.

What they're saying: Boychenko told AP that corpses were "carpeted through the streets" of Mariupol and accused Russian forces of intentionally refusing to allow humanitarian convoys into the city in an attempt to conceal the carnage.

• He also said Russia was attempting to destroy evidence of civilian deaths by burning bodies with mobile cremation equipment.
• Ukrainian President Volodymyr Zelensky told South Korean lawmakers Monday that there "are tens of thousands of dead” in Mariupol.

The United Nations Human Rights Council, from which Russia was suspended last week, estimates that at least 1,842 civilians have been killed and 2,493 injured during the invasion, though it stressed that its estimates were likely considerably lower than the actual figures because ongoing fighting has delayed it documentation efforts

• At least 300 people were killed by a Russian airstrike on a theater in Mariupol, where Russian forces also struck an art school, a mosque and a children's hospital and other civilian buildings.

Go deeper: France sends experts to investigate possible war crimes in Ukraine