Ukrainian prisoners of war (POWs) ride atop of an infantry fighting vehicle after a swap, amid Russia's attack on Ukraine, in Donetsk region, Ukraine May 25, 2023. REUTERS/Yevhenii Zavhorodnii

Ukrainian servicemen carry a coffin with the body of a person who is considered to be former U.S. Army soldier Nicholas Maimer, killed in the frontline town of Bakhmut, after prisoners of war (POWs) swap, amid Russia's attack on Ukraine, in Donetsk region, Ukraine May 25, 2023. REUTERS/Yevhenii Zavhorodnii TPX IMAGES OF THE DAY

Ukrainian prisoners of war (POWs) are seen after a swap, amid Russia's attack on Ukraine, in Donetsk region, Ukraine May 25, 2023. REUTERS/Yevhenii Zavhorodnii

Ukrainian prisoners of war (POWs) are seen after a swap, amid Russia's attack on Ukraine, in Donetsk region, Ukraine May 25, 2023. REUTERS/Yevhenii Zavhorodnii

Ukrainian prisoners of war (POWs) ride atop of an infantry fighting vehicle after a swap, amid Russia's attack on Ukraine, in Donetsk region, Ukraine May 25, 2023. REUTERS/Yevhenii Zavhorodnii TPX IMAGES OF THE DAY

Ukrainian prisoners of war (POWs) are seen after a swap, amid Russia's attack on Ukraine, in Donetsk region, Ukraine May 25, 2023. REUTERS/Yevhenii Zavhorodnii

A Ukrainian prisoner of war (POW) is seen after a swap, amid Russia's attack on Ukraine, in Donetsk region, Ukraine May 25, 2023. REUTERS/Yevhenii Zavhorodnii

Ukrainian prisoners of war (POWs) are seen after a swap, amid Russia's attack on Ukraine, in Donetsk region, Ukraine May 25, 2023. REUTERS/Yevhenii Zavhorodnii

A Ukrainian prisoner of war (POW) is seen after a swap, amid Russia's attack on Ukraine, in Donetsk region, Ukraine May 25, 2023. REUTERS/Yevhenii Zavhorodnii

Ukrainian prisoners of war (POWs) are seen after a swap, amid Russia's attack on Ukraine, in Donetsk region, Ukraine May 25, 2023. REUTERS/Yevhenii Zavhorodnii

Ukrainian prisoners of war (POWs) are seen after a swap, amid Russia's attack on Ukraine, in Donetsk region, Ukraine May 25, 2023. REUTERS/Yevhenii Zavhorodnii

A Ukrainian prisoner of war (POW) is seen after a swap, amid Russia's attack on Ukraine, in Donetsk region, Ukraine May 25, 2023. REUTERS/Yevhenii Zavhorodnii

A Ukrainian prisoner of war (POW) is seen after a swap, amid Russia's attack on Ukraine, in Donetsk region, Ukraine May 25, 2023. REUTERS/Yevhenii Zavhorodnii

Ukrainian prisoners of war (POWs) are seen after a swap, amid Russia's attack on Ukraine, in Donetsk region, Ukraine May 25, 2023. REUTERS/Yevhenii Zavhorodnii

Ukrainian prisoners of war (POWs) are seen atop and next to an infantry fighting vehicle after a swap, amid Russia's attack on Ukraine, in Donetsk region, Ukraine May 25, 2023. REUTERS/Yevhenii Zavhorodnii

Ukrainian servicemen carry a coffin with the body of a person who is considered to be former U.S. Army soldier Nicholas Maimer, killed in the frontline town of Bakhmut, after prisoners of war (POWs) swap, amid Russia's attack on Ukraine, in Donetsk region, Ukraine May 25, 2023. REUTERS/Yevhenii Zavhorodnii