Kim Jong Un has met the families of soldiers killed fighting for Russia against Ukraine, expressing his deep condolences, North Korean state media reports.

In a special ceremony held on Friday, the North Korean leader was seen comforting bereaved families and presenting them portraits of their deceased loved ones wrapped in the nation's flag.

South Korea believes North Korea has sent around 15,000 troops to assist Russia in its invasion, with reports indicating that in exchange, North Korea has received food, money, and technical assistance.

North Korea only acknowledged its participation in the foreign conflict in April, admitting to some losses among its soldiers.

According to Western officials, at least 1,000 North Korean troops were believed to have been killed within three months of deployment, although more recent estimates suggest a death toll closer to 600.

This ceremony was the second of its kind within a week. Kim expressed sorrow over the loss of life, promising to erect a monument in their honor and to take care of their children.

I thought a lot about other martyrs' families who were not present [at the previous ceremony]... So, I had this meeting arranged as I wanted to meet and console the bereaved families of all the heroes and relieve them of their sorrow and anguish even a little, state news agency KCNA quoted Kim.

Next week, Kim is set to meet Russian President Vladimir Putin in China, marking their third meeting in two years as cooperation between Moscow and Pyongyang intensifies. Last October, Kim sent Putin a birthday message, referring to him as his closest comrade.

North Korea has about 1.28 million active soldiers but had limited combat experience abroad until the deployment to Ukraine.