North Korea sent its best troops to aid Russia in its war against Ukraine. But after months of suffering severe losses, they have been taken off the front line.

South Korea’s Joint Chiefs of Staff also assessed in a report Friday that North Korea is continuing its preparations to test-fire an intercontinental ballistic missile.

North Korea has not responded to reports of its troops captured or killed by Ukraine forces. It has never publicised the deployment or large shipments of North Korean artillery shells and other weapons sent to Russia to help its war against Ukraine, although they marked the country’s first intervention in a major armed conflict overseas in decades.

North Korea and Russia's deepening military relationship has sounded alarm in South Korea and the United States.

British intelligence has reported that one-third of the troops deployed alongside Russian forces in Ukraine are already out of action. Pyongyang sent a contingent of 12,000 soldiers to Russia to assist local forces in regaining lost territory in the Kursk region,