Washington has said the treatment of Glavprodukt, the only U.S. company Moscow has seized, will influence a planned reset of U.S.-Russia relations.

South Korea sent six North Koreans back across their sea border, months after they drifted south in wooden boats in March and May.

The Wonsan Kalma resort was opened in a grand ceremony last month by North Korea's leader, Kim Jong Un, who hailed it as a "world-class tourist and cultural destination". The details of how this resort was built have been shrouded in secrecy in a country largely closed to the outside world.

Russia Partnership in Ukraine: In exchange for sending tens of thousands of troops and vast amounts of artillery shells to aid Russia’s war in Ukraine, North Korea is likely demanding and receiving critical Russian military technology.