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.

Leader Kim Jong Un pledged to pursue "sustained countermeasures," citing security ties between the U.S. and its regional allies.

Kim Jong Un condemns US, Japan and South Korea military ties and vows nuclear countermeasures - Kim condemned the deployment of US nuclear assets and joint military exercises in the region

North Korean leader Kim Jong Un has pledged to further develop the country's nuclear arsenal, citing increasing security threats from the United States, South Korea, and Japan. In a speech marking the 77th anniversary of the Korean People's Army,