North Korean leader Kim Jong Un threatened to use nuclear weapons against South Korea “without hesitation” if the U.S.-ROK alliance “infringes” on Pyongyang’s sovereignty, according to state media on Friday, disparaging the South’s president as “abnormal” for attempting to intimidate a nuclear neighbor.

The party daily Rodong Sinmun reported that Kim delivered the threat during a visit to a special forces unit on Wednesday, a day after South Korea held a military parade featuring its new “monster” ballistic missile and a flyover by U.S. strategic bomber.

In his remarks, the North Korean leader referred to ROK President Yoon Suk-yeol by