North Korea's leader, Kim Jong Un, has met the families of soldiers killed fighting for Russia against Ukraine and expressed his deep condolences, state media reports.

In a special ceremony held on Friday Kim was seen comforting bereaved families and presenting them portraits of their dead loved ones wrapped in the North Korean flag.

South Korea believes the North has sent approximately 15,000 troops to aid Russia's war with Ukraine, along with missiles and long-range weapons. In return, it's believed North Korea has received food, money, and technical help.

North Korea only acknowledged its role in the foreign conflict in April, admitting that some of its soldiers had been killed.

In January, Western officials informed the BBC that they believed at least 1,000 of the troops sent from North Korea had been killed in three months, with several thousand more wounded, but recent estimates have indicated the number closer to 600 killed.

Friday's ceremony marked the second of its kind in a week. During the event, Kim expressed his sorrow at failing to bring the soldiers back alive, pledging to construct a monument in their honor and take care of their children.

I thought a lot about other martyrs' families who were not present [at the previous ceremony]... Thus, I arranged this meeting to console the bereaved families of all the heroes and alleviate their sorrow and anguish a little, KCNA reported Kim as stating.

Kim is set to meet with Russia's Vladimir Putin in China next week to attend a military parade commemorating Japan's surrender in World War II.

This meeting will be their third in two years, during a time when Moscow and Pyongyang are strengthening their cooperation, with relations between both countries reaching unprecedented heights.

Last October, Kim sent Putin a birthday message, referring to him as his closest comrade. That same month, Putin introduced a bill to ratify a military pact with Kim, which stipulates mutual assistance in the event of aggression against either country.

North Korea may have around 1.28 million active soldiers, but prior to the Ukraine deployment, its army lacked recent experience with combat operations overseas.