Hundreds of Ukrainian troops have surrendered at the Mariupol Steel Plant, according to Russia.

Russia said on Tuesday that 265 Ukrainian soldiers had surrendered after a last standoff at the besieged Azovstal steelworks in Mariupol, forcing Kiev to seek a prisoner swap.

After a weeks-long assault, Moscow took control of the vital port city last month, but hundreds of Ukrainian forces remained holed up in tunnels beneath the massive Azovstal industrial zone.

“In the last 24 hours, 265 terrorists put down their guns and surrendered, including 51 gravely injured,” according to the Russian defense ministry.

It said the injured were sent to a hospital in eastern Donetsk region controlled by pro-Kremlin rebels after sharing photographs of wounded personnel being carried on stretchers.