A British volunteer fighting alongside Ukrainian marines in besieged Mariupol has surrendered to Russian forces, according to reports. The BBC’s Emma Vardy revealed on Twitter that Aiden Aslin’s family confirmed he had been forced to surrender. She quoted Aslin’s mother as saying “he called me and said they had no weapons left” though they “put up one hell of a fight.” Aslin had been posting about the war on an Instagram account that had been taken down by the time reports of his surrender surfaced Tuesday. His whereabouts are unknown, but a Twitter account affiliated with Aslin said to “hope for a prisoner exchange.” Aslin, 28, has been part of Ukraine’s military since 2018. He would be the first known British prisoner of war in Vladimir Putin’s “special operation” against Ukraine if taken alive. In comments to The Telegraph last month, he warned of a deteriorating situation in Mariupol, saying “mass war crimes are being committed by Russian forces, they are targeting anyone they see, regardless if they are civilians.”