North Korea is set to treble the number of its troops fighting for Russia along the front lines with Ukraine, sending an additional 25,000 to 30,000 soldiers to assist Moscow, according to an intelligence assessment from Ukrainian officials.

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.

Russia and North Korea are meeting for a three-day visit that is already sending other countries into a tailspin, as World War 3 fears mount.

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.

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

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.