North Korean leader Kim Jong Un ordered the "expansion" and modernization of the country's missile production next year and the construction of more factories to meet growing demand, state media said Friday.

In a visit to munitions factories accompanied by top officials, the state-run Korean Central News Agency (KCNA) said Kim had ordered the factories to meet "prospective requirements in the operation of the state missile and artillery forces".

Kim said they would need "to further expand the overall production capacity" in order to keep pace with demand from Pyongyang's armed forces and ordered the building of new munitions plants, KCNA reported.

"The missile and shell production sector is of paramount importance in bolstering up the war deterrent," the North Korean leader said.

Pyongyang has significantly increased missile testing in recent years.

Analysts say this is aimed at improving precision strike capabilities, challenging the United States as well as South Korea, and testing weapons before potentially exporting them to Russia.

Kim's visit was reported a day after state media said he had toured a nuclear submarine factory, where he vowed to counter the "threat" of South Korea producing its own such vessels.

He also learned about research into "new underwater secret weapons", KCNA said.

Kim was also reported to have overseen the test launch of new-type high-altitude long-range anti-air missiles over the Sea of Japan.

North Korea's ruling Korean Workers Party is expected to hold its first congress in half a decade in early 2026, where policymakers will hash out economic and military development plans for the next five years.