North Korean leader Kim Jong Un criticized trilateral military cooperation among the United States, Japan and South Korea for raising tensions in the region and vowed countermeasures, including the further development of nuclear forces, Report informs via Reuters.

Kim said US deployments of nuclear strategic assets, war exercises and military cooperation with Japan and South Korea were inviting military imbalance in the region and raising a grave challenge to the security environment, state media KCNA reported on Sunday.