A Russia-backed rebel looks at the flag covered body of an Ukrainian serviceman in Debaltseve, Ukraine, February 20, 2015. The struggle for the strategic rail hub, Debaltseve, a sleepy town with a pre-war population of 25,000 people, left the town in ruins and became one of the darkest pages in the ongoing conflict in eastern Ukraine, which has already killed more than 6,000 people. (Photo by Vadim Ghirda/AP Photo/File)

A slogan and crosses are painted on the helmet of a Ukrainian serviceman in Ruska Lozova, a village retaken by the Ukrainian forces, amid Russia's attack on Ukraine, in Kharkiv region, Ukraine on May 16, 2022. (Photo by Ricardo Moraes/Reuters)

A Ukrainian serviceman smokes a cigarette at his position at the frontline near Bakhmut, Donetsk region, Ukraine, Wednesday, January 11, 2023. (Photo by Evgeniy Maloletka/AP Photo)

Ukrainian servicemen of the State Border Guard Service wait for an order to move to the mortar position at the entrance of the shelter in Bakhmut on February 16, 2023, as the head of Russia's mercenary outfit Wagner said it could take months to capture the embattled Ukraine city and slammed Moscow's “monstrous bureaucracy” for slowing military gains. (Photo by Yasuyoshi Chiba/AFP Photo)

Ukrainian service man Oleksandr of 24th brigade stands guard at his position in the trenches at the frontline, amid Russia?s attack on Ukraine near Niu York, Donetsk region, Ukraine on April 4, 2023. (Photo by Kai Pfaffenbach/Reuters)

A Ukrainian serviceman takes a rest near the town of Bakhmut, in the Donetsk region on April 28, 2023, amid the Russian invasion on Ukraine. (Photo by Dimitar Dilkoff/AFP Photo)

Ukrainian service members of the 3rd Separate Assault Brigade attend military exercises near the town of Bakhmut, amid Russia's attack on Ukraine, in Donetsk region, Ukraine on September 7, 2023. (Photo by Reuters/Stringer)

Members of a newly-formed “Siberian Battalion” within the Ukrainian Armed Forces take part in a military training exercise outside Kyiv on October 24, 2023, amid the Russian invasion of Ukraine. A newly formed “Siberian Battalion” as part of the International Legion within the Ukrainian Armed Forces is made up of Russians who have come to fight against their fellow citizens. They were a varied group-both ethnic Russians with long-standing opposition views and members of minority ethnic groups. (Photo by Genya Savilov/AFP Photo)