N Korea Breaks Contact With US in Response to Sanctions Against Leadership

The test-fire of a submarine-launched ballistic missile at an undisclosed location in North Korea in April 2016

The test-fire of a submarine-launched ballistic missile at an undisclosed location in North Korea in April 2016

The test launch comes a day after the US and South Korea joined forces to deploy the Terminal High-Altitude Area Defense (THAAD) system to counter North Korean missiles.

Pyongyang, on the other hand fired back at Washington after the announcement of the deployment, warning that North Korea would instantly cut off all diplomatic channels with the US if the sanctions were not lifted.

The North frequently threatens to attack the South and US interests in Asia and the Pacific.

And it's hinting at harsher punishment for Americans detained in the country.

Also on Monday, Pyongyang threatened to take "physical action" after Washington and Seoul announced they would deploy a sophisticated United States anti-missile defence system to counter the growing menace from Pyongyang.

"We once again warn the enemies that it is the steadfast will of the Korean People's Army to make merciless retaliatory strikes to reduce South Korea to a sea of flames and debris once an order is issued", read the statement from Pyongyang's general staff department's military artillery bureau.

North Korea and the United States remain technically at war because the 1950-53 Korean War, in which Washington sided with the South, ended only with a truce. The North first claimed a successful submarine-launched missile test in May previous year.

Moon Sang-guyn, a spokesman for South Korea's Defense Ministry, warned the North to not take "rash and foolish action". This is needed because the countries don't have diplomatic ties and their animosities have deepened because of the North's nuclear and missile programs.

The tense situation persists on the Korean Peninsula "due to the fault of the United States", a representative of North Korean Foreign Ministry said on Monday.

The North's actions could complicate US efforts to secure the release of at least two American citizens being held for alleged espionage, subversion and other anti-state activities.

"These actions, and North Korea's continued pursuit of ballistic missile and nuclear weapons capabilities, pose a significant threat to the United States, our allies, and to the stability of the greater Asia-Pacific", she said.

US and South Korean officials say THAAD only targets North Korea, but China and Russian Federation suspect it could also help USA radars detect their own missiles.

China and Russian Federation have explicitly expressed opposition against the THAAD deployment in South Korea on concerns that the move could hurt their strategic security interests.

A South Korean Defense Ministry official said the selection of a site for THAAD would come "within weeks", and it and the U.S. plan to have it operational by the end of 2017.

In March, the U.N. Security Council imposed its toughest sanctions to date on North Korea for its fourth nuclear test and long-range rocket launch in the following month.

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