LVIV, March 28 - Nearly 5,000 people, including about 210 children, have been killed in the southern Ukrainian city of Mariupol since Russian forces laid siege to it, Reuters reported Monday citing a spokesperson for the mayor.

It was not immediately clear how Mayor Vadym Boichenko had calculated the toll from a month of Russian bombardment that has devastated the city and trapped tens of thousands of residents without power and with few supplies.

Boichenko's office said 90% of Mariupol's buildings had been damaged and 40% destroyed, including hospitals, schools, kindergartens and factories.

About 140,000 people had fled the city on the Sea of Azov before the Russian siege began and 150,000 have exited since then, leaving 170,000 still there, according to its figures, which Reuters could not immediately verify.

Boichenko, who is no longer in Mariupol, said on national television earlier on Monday that about 160,000 civilians were still trapped in the city.

"People are beyond the line of humanitarian catastrophe," he said. "We need to completely evacuate Mariupol."

Ukraine said it was impossible to create any safe corridors on Monday, citing intelligence reports about possible Russian "provocations" along the routes.

Russia, which invaded Ukraine on Feb. 24, denies targeting civilians and blames Ukraine for repeated failures to agree on safe corridors for trapped residents.

"The Russian Federation is playing with us. We are in the hands of the invaders," Boichenko said.

The two sides are set to resume peace talks on Tuesday in Turkey.

Mariupol is widely seen as a strategic prize as its capture could enable Russia to create a land bridge between Crimea, annexed by Moscow in 2014, and two separatist enclaves in eastern Ukraine.

People who have fled Mariupol have been describing how tough it was living for weeks under almost constant bombardment.

"There is no food for the children, especially the infants. They delivered babies in basements because women had nowhere to go to give birth, all the maternity hospitals were destroyed," a grocery worker from Mariupol who gave her name only as Nataliia told Reuters after reaching nearby Zaporizhzhia.

"I also found out today that my son's classmate's parents were torn apart right in the yard before his eyes." (rt/ez)