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North Korea's military on Sunday night threatened a "physical response" to a move by the United States and South Korea to deploy the advanced THAAD missile defense system to the Korean peninsula to counter the threat from the North, Reuters reports.

The United States and South Korea said on Friday that the Terminal High Altitude Area Defense (THAAD) anti-missile system will be used as defense against North Korea's growing nuclear and ballistic missile capabilities.

The announcement was the latest move by the allies against the North, which conducted its fourth nuclear test this year and launched a long-range rocket, resulting in tough new UN sanctions and a series of bilateral sanctions against it.

The tensions with North Korea escalated last week, when Washington blacklisted North Korean leader Kim Jong Un over human rights abuses.

Kim responded by threatening a tough response to what he called the United States' “declaration of war” against Pyongyang.

"There will be physical response measures from us as soon as the location and time that the invasionary tool for U.S. world supremacy, THAAD, will be brought into South Korea," the North's military said in a statement on Sunday night, according to Reuters.

"It is the unwavering will of our army to deal a ruthless retaliatory strike and turn (the South) into a sea of fire and a pile of ashes the moment we have an order to carry it out," the statement carried by the official KCNA news agency added.

The North frequently threatens to attack the South and U.S. interests in Asia and the Pacific. In fact, Kim several weeks ago boasted that his country possesses "the sure capability to attack" U.S. interests in the Pacific.

North Korea has been under UN sanctions since 2006. In March, the Security Council imposed harsh new sanctions on the country in response to North Korea's fourth nuclear test in January and the launch of a long-range rocket in February.

President Barack Obama in March imposed sanctions on broad sectors of the North Korean economy in response to its ongoing missile tests.