The "new mayor" of Mariupol, put in place by pro-Russian forces, announced on Thursday that around 5,000 civilians had died in the besieged southeastern Ukrainian city.
"Around 60-70% of the housing stock has been destroyed or partially destroyed," said Konstantin Ivashchenko, who was named as the town's mayor on Wednesday by Denis Pushilin, leader of the separatists in the breakaway Donetsk region.
Cited by the Russian TASS news agency, Ivashchenko that 250,000 people had left Mariupol.
The quotes are excerpts from an interview which TASS said would be published on Friday.
Ukrainian authorities had put forward a "conservative" estimate of 5,000 dead, while indicating that there could be "tens of thousands of civilian casualties" in the city, which they say is 90% destroyed.
The Russian army and its separatist allies have been besieging Mariupol for weeks but are facing fierce Ukrainian resistance.
The humanitarian situation there is catastrophic, according to both sides.
