North Korea is ready to use the “most overwhelming nuclear force” in response to any U.S. military challenges, Pyongyang’s Foreign Ministry said in a statement Thursday. The furious rhetoric comes as Kim Jong Un’s regime has been outraged by increased American military cooperation with South Korea.

On Tuesday, Defense Secretary Lloyd Austin vowed to send more aircraft carriers and fighter jets to the region. In response, the unnamed North Korean spokesperson said Washington, D.C., risked turning the Korean peninsula into a “huge war arsenal and a more critical war zone.” “The military and political situation on the Korean peninsula and in the region has reached an extreme red line due to the reckless military confrontational maneuvers and hostile acts of the U.S. and its vassal forces,” the North Korean spokesperson added in the statement.