The threat came as the two Cold War foes prepared for ceremonies marking the 50th anniversary of the signing of the cease-fire to end the three-year war.

The North's ruling Workers Party newspaper, Rodong Sinmun, said Pyongang would take a "strong step" to pull out the agreement if Washington built up its forces on the peninsula and imposed a blockade on the Stalinist state.

The United States had misused the armistice "for serving their despicable purpose" and worked hard to "bedevil" inter-Korean relations, it charged.

"The reality goes to clearly prove who is chiefly to blame for the tensions and the danger of war on the Korean peninsula and who truly wants peace and stability or who is their wicked disturber," Rodong said.

It said the armistic accord (AA) was "fated to be abrogated when any party pulls out of it."

"If the US persists in its moves to start a war against the DPRK (North Korea), it can no longer remain bound to the defunct AA to leave the peace of the country and the destiny of the nation to the tender mercy of outside forces and stay idle."

The armistice was signed between the US-led United Nations Command, China and North Korea, three years after the war broke out on June 25, 1950.

South Korea refused to signed the accord, which has left the two Koreas technically in a state of war. Instead, South Korea forged a mutual defense pact with the United States to keep US forces here.

Some 1,500 veterans from 21 nations who supported the UN side prepared for a ceremony in the border truce village of Panmunjom in the buffer zone that divides the two Koreas.

North Korea snubbed an offer to join UN forces in the ceremony and plans to hold a separate ceremony by inviting pro-communist foreign delegates to an international conference.

North Korea has celebrated the anniversary as the day of victory, designating the one-month period from June 25 to July 27 as the "month of anti-US Joint struggle."

Since the armistice was signed, the world's most heavily fortified Cold War frontier has remained a dangerous military flashpoint, manned by more than one million troops from both sides.

WAR.WIRE