The North Korean leader said the partnership poses a grave threat to his country and vowed to further bolster his nuclear weapons program.

SEOUL (Reuters) -North Korean leader Kim Jong Un criticised trilateral military cooperation among the United States, Japan and South Korea for raising tensions in the region and vowed countermeasures,

The first tour is set to take place Feb. 12 to 18, when major celebrations are planned for the birthday of the country's late leader Kim Jong Il, one of North Korea's biggest holidays.