Russia-Ukraine Crisis: Moscow will consider exchanging prisoners from Ukraine’s Azov battalion for Viktor Medvedchuk, a wealthy Ukrainian businessman close to President Vladimir Putin, a Russian negotiator said on Saturday.

With Russia claiming to have taken prisoner nearly 2,500 Ukrainian fighters from the besieged Mariupol steel plant, concerns grew about their fate as a Moscow-backed separatist leader vowed they would face tribunals.

The Ukraine war can only be resolved through “diplomacy”, Ukrainian President Volodymyr Zelensky said Saturday amid a deadlock in negotiations between Kyiv and Moscow. “The end will be through diplomacy,” he said.

Russia claimed on Friday to have complete control of the port city of Mariupol, in what would be its most significant symbolic gain since the war started. Moscow said that its defence minister had informed President Putin of the “complete liberation” of the Mariupol steel plant where Ukrainian fighters made their last stand in the city before surrendering in recent days.