North Korean leader Kim Jong Un has vowed to bolster his nuclear weapons program in response to the U.S.’s enhanced security partnership with South Korea and Japan. Last year, the U.S. expanded bilateral military exercises with South Korean and trilateral training with South Korea and Japan.

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

North Korean leader Kim Jong-un threatens to step up all deterrence measures, including nuclear capabilities. According to intelligence reports, Kim Jong-un has sent thousands of soldiers to Moscow to fight in the war in Ukraine.