This is the latest in a series of Russian top visits to the closed country. Lavrov has visited Pyongyang several times this year, most recently as late as June.
Russia and North Korea signed a military agreement last year that includes a clause on mutual defense.
The dictatorship on the Korean peninsula has become one of Russia's closest allies during the more than three-year war being waged against neighboring Ukraine. Among other things, North Korean soldiers and containers full of weapons have been sent to Moscow to stop the Ukrainian advance in the Russian region of Kursk, which began last summer.