In one of the most critical battles of the war, Russia’s defence ministry said on Wednesday 1,026 soldiers from Ukraine’s 36th Marine Brigade, including 162 officers, had “voluntarily laid down their arms” near the city’s Ilyich iron and steelworks.

There was no independent confirmation of the claim. Ukraine’s defence ministry said it had no information about the surrender and the Ukrainian military command said only that Russian forces were attacking the Azovstal industrial area and the port.

The Chechen leader, Ramzan Kadyrov, who says his forces are playing a major role in the battle, urged the last Ukrainians holed up in Azovstal to surrender. The 26th Marine Brigade had said on Monday it was preparing for a final battle in Mariupol.