N. Korea severs key diplomatic communication channel with U.S.

North Korea also said in the message sent to the United States on Sunday that it will address all problems between the two countries under its "wartime law," adding that the issue of U.S. nationals detained by Pyongyang is no exception, according to the state-run Korean Central News Agency.

A day after the United State sanctioned Kim and other senior officials for their "notorious" abuses of human rights, North Korea urged Washington to immediately remove the punitive measures, threatening that otherwise Pyongyang would close all bilateral diplomatic channels.

The United States has rejected North Korea's demand.

In the message, North Korea, which has no formal diplomatic relations with the United States, said again that the sanctions have "impaired the dignity of the supreme leadership" and it deems them to be a "declaration of war" against Pyongyang.

North Korea said it will take "practical actions" against the United States "stage by stage" and the severance of the only official communication means, known as the "New York channel," is just the first phase.

North Korea had mainly used its permanent mission to the United Nations to communicate with the United States.

Pyongyang told the United States that Washington must be responsible for all unforeseen circumstances which could happen regarding their relations, according to KCNA.

The notification could further complicate Washington's efforts to secure the release of two detainees, Kim Dong Chul, a 62-year-old Korean-American man, and Otto Warmbier, a student of the University of Virginia.

In mid-March, North Korea's highest court sentenced Warmbier to 15 years of hard labor, saying he had tried to steal an item with a political slogan from a staff-only area of a hotel.

The Supreme Court sentenced Kim in late April to 10 years of hard labor for carrying out what it described as espionage and subversion activities.

Source: Kyodo