Kim hosted the families of soldiers and expressed "grief at having failed to save the precious lives" of the fallen men who sacrificed their lives to defend the country's honour, KCNA state news agency reported.
The heroic feats of the soldiers and officers were possible because of the strength and courage given to them by families who are "the most tenacious, patriotic and just people in the world", Kim told the parents, wives and children, KCNA said.
"They did not write even a short letter to me, but I think they must have entrusted their families, including those beloved children, to me," Kim was quoted as saying.
The nation will "provide you with a beautiful life in the country defended at the cost of the lives of the martyrs", he said.
The meeting was the latest honouring of troops who suffered heavy casualties in Russia's Kursk region that borders Ukraine, after Kim and Russian President Vladimir Putin acknowledged the deployment in April after months of silence.
Kim is due to stand with Putin in China at a military parade next week marking the surrender of Japan in World War II.
It will be their third meeting in two years as they dramatically elevated a military alliance.
The two nations have not publicly disclosed the scale of the deployment or casualties suffered by North Korean troops.
About 600 have been killed of a total deployment of 15,000, according to South Korea's intelligence agency.
There have been estimates by Western intelligence of more than 6000 casualties.
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