North Korea is expanding a weapons plant that manufactures missiles used by Russia against Ukraine, according to new research from a US-based think tank.

North Korea is expanding a key weapons manufacturing complex that assembles a type of short-range missile used by Russia in Ukraine, researchers at a U.S.-based think tank have concluded, based on satellite images.

Russia's Deputy Foreign Minister Andrey Rudenko issued a warning to South Korea against supplying lethal aid to Ukraine, saying that the move would "fully destroy relations" between the two countries.