According to North Korean state media KCNA news agency, Kim and Lavrov met on Saturday in “an atmosphere full of warm comradely trust”.
The North Korean leader also expressed a “firm belief that the Russian army and people would surely win victory in accomplishing the sacred cause of defending the dignity and basic interests of the country”.
On Telegram, Russia’s foreign ministry posted a video showing the two men shaking hands and greeting each other with a hug.
North Korea’s renewed military support for Russia comes as US President Donald Trump has resumed military supplies to Ukraine, after a brief hiatus.
Trump told NBC News on Thursday that he had made a deal with Nato for the US to send Patriot air defence systems to Ukraine via the alliance, after a surge of Russian aerial attacks.
Pyongyang first publicly acknowledged sending troops to Russia in April, months after Ukraine and the West revealed the large-scale troop movement from North Korea to the Russian-Ukrainian frontline.
Kim signed an accord with Russian leader Vladimir Putin in June last year, agreeing to support each other if either country was dealing with “aggression”.
Apart from soldiers, North Korea also promised to send thousands of workers to help rebuild Russia’s war-torn Kursk region, Moscow’s security chief said last month.