North Korean leader Kim Jong-un reportedly sent New Year’s messages to North Korean soldiers deployed in Russia's war against Ukraine, urging them to "fight with courage" until the end, according to a news report.

Ukraine President Volodymyr Zelensky reported that more than 3,800 North Korean soldiers have already been killed in the Kursk region.

The soldiers of the Korean People's Army captured from the front lines of the war in Ukraine appeared unwilling to defect from North Korea.

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 Korean troops have been deployed to bolster Russian forces in the Kursk border region with Ukraine, where they are gaining battlefield experience despite initial heavy losses.

North Korea's deployment to Russia is its first major involvement in a war since the 1950-53 Korean War. North Korea reportedly sent a much smaller contingent to the Vietnam War and to the civil conflict in Syria. The United States has warned the experience in Russia will make North Korea "more capable of waging war against its neighbours".

According to Ukrainian President Volodymyr Zelensky, North Korean soldiers were transported to Russian territory by ferry, then by train, and kept in total isolation as far as information was concerned.