Information about possible cooperation with the Russians of the Ukrainian serviceman, who was released as part of the 54th prisoner exchange, is now being checked, the 35th Separate Marine Brigade named after Rear Admiral Mykhailo Ostrogradsky and the Main Intelligence Agency of the Ministry of Defense of Ukraine said.

"The news is spreading in the media about cooperation with Russian invaders during the captivity of one of our servicemen released today. We officially inform you that information about this fact is now being carefully checked," the 35th brigade said on Facebook.

The brigade said if the facts stated in the media are confirmed, appropriate decisions will be made within the framework of the current legislation.

The Intelligence Agency's representative Andriy Yusov said on Radio Liberty that this story was being followed.

"If there are certain facts that require verification and additional attention, including from the point of view of counterintelligence aspects, then such work is carried out," he said.

Former prisoner of war and participant in the air breakthrough into Mariupol, Viktor "Leleka" Lakhno, said one of the soldiers who was exchanged was involved in the beating of Azov fighters and wanted to obtain Russian citizenship.