Moscow announced in November that its forces had captured James Anderson, describing him as a former British soldier.
Meanwhile, Russian forces are focusing their attacks on the outskirts of the key eastern Ukrainian city of Pokrovsk amid reports of heavy troop losses.
Around half of Russian attacks across the 620-mile front have focused on the area around the city, seen as a gateway to the rest of the Donetsk region, over the last week, Kyiv said.
“The enemy is trying to advance around the clock,” Maksym Bakulin, a spokesperson for the Ukrainian National Guard units fighting in Pokrovsk, said.
The Russian defence ministry claimed its troops had taken control of the village of Novoielyzavetivka, less than 10 miles to the southwest of Pokrovsk.
The Ukrainian military has not confirmed Russia’s claims but DeepState, a Ukrainian war tracker known to have close ties to the military, records the town as being occupied.
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