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.

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

North Korean troops' limited combat experience and unfamiliarity with the terrain of the Russian-Ukrainian battlefields have contributed to heavy losses.