North Korea on Friday scrapped all non-aggression pacts with South Korea following tough new sanctions slammed against the reclusive state over its third nuclear test.

The official KCNA news agency says the North is cancelling all non-aggression pacts with the South, cutting off its hotline with Seoul and closing the main Panmunjom border crossing in the Demilitarized Zone.

“It notifies the South side that it will immediately cut off the North-South hotline,” the state-run Committee for the Peaceful Reunification of Korea said in a statement, carried by KCNA.

North Korean leader Kim Jong-Un reportedly visited front-line military units that were involved in the 2010 shelling of a South Korean island and urged troops there to keep themselves ready to “annihilate the enemy” at any time, BBC reports.

The North vowed to carry out a pre-emptive nuclear strike against the United States ahead of UN Security Council sanctions aimed at further isolating the North.

“As long as the United States is willing to spark nuclear war, our forces will exercise their right to a pre-emptive nuclear strike,” North Korea’s foreign ministry said in the statement carried by KCNA.

The Security Council unanimously voted to approve the tougher measures which targets North Korean diplomats, cash transfers and exports of luxury goods.

Speaking after the vote, US ambassador to the UN Susan Rice warned that the UN would “take further significant actions” if Pyongyang conducts another nuclear test.