Russia announced it would observe a partial ceasefire in Ukraine to allow civilians to evacuate from two encircled cities, hours after it was accused of breaking international law by using cluster bombs.

The defence ministry claimed this morning that humanitarian corridors would be opened in the areas of Volnovakha and Mariupol with the agreement of Ukrainian authorities.

However, after the ceasefire was declared at 10am Moscow time (7am GMT), city officials in Mariupol said Russian troops were not fully observing the agreement. “We are simply being destroyed,” Mariupol mayor Vadym Boychenko said.

The Ukrainian government said it was looking into reports that Russia was using the ceasefire to advance towards Mariupol while continuing its offensive elsewhere. The plan had been to evacuate around 200,000 people.