This is reported by the South Korean news agency "Yonhap" with reference to the North Korean Central News Agency (KCNA).
It is noted that the head of the DPRK took such a step because of the hostile, in his opinion, policy of Washington.
North Korea has vowed to prepare for a lengthy confrontation with the United States.
Earlier, US Special Representative for North Korea Sung Kim held telephone conversations with South Korea's Special Representative for Peace and Security on the Korean Peninsula No Gyu Deok and Director General of the Asia and Oceania Department of the Japanese Foreign Ministry Funakoshi Takehiro.