BBC: Pyongyang has sent at least 10,000 troops to Russia, according to Kyiv and Seoul, who have also said North Korean casualties have been rising since entering combat in early December.
The tolls cited vary. South Korea said this week that more than 1,000 North Korean troops have been killed or wounded, while Ukrainian President Volodymyr Zelensky put the number at 3,000.
“What they lack in combat they make up for with what they can tolerate physically and mentally,” he adds.