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 says. 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 some 15,000 troops to aid Russia's war with Ukraine, along with missiles and long-range weapons. In return, it is believed North Korea 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 told the BBC 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 more recent estimates have put the figure closer to 600 killed.

Friday's ceremony was the second of its kind in a week. During the event, Kim said he was filled with sorrow at failing to bring the soldiers back alive, pledging to build a monument in their honour and to look after 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, KCNA reported Kim as saying.

Kim is due to meet Russia's Vladimir Putin in China next week when he travels to attend a military parade marking Japan's surrender in World War II. This will be their third meeting in two years, coinciding with the deepening of cooperation between Moscow and Pyongyang. In the past year, Kim has referred to Putin as his closest comrade, and both leaders have pledged mutual support in the event of aggression against either country.

Despite having an active force of around 1.28 million soldiers, North Korea had not engaged in foreign combat operations until the recent involvement in Ukraine.