Hyunseung Lee, a former soldier who fled North Korea, told BI that those sent to fight against Ukraine have "zero relationship with modern warfare."

Over 12,000 North Korean troops are estimated to be fighting against Ukrainian forces in Russia’s Kursk region, the United Nations Security Council learned last week.

South Korea's military suspects North Korea is preparing to send more troops to Russia to fight Ukrainian forces, following reports of heavy casualties among North Korean soldiers due to a lack of modern combat training.