SEOUL - South Korea said Tuesday it refused to recognise North Korea's move to unilaterally scrap the 60-year-old Korean War armistice, and urged Pyongyang to row back on its recent warlike rhetoric.

The North announced last week its intention to shred the armistice and other bilateral peace pacts signed with Seoul if South Korea and the United States went ahead with an annual joint military exercise.

The joint drill was launched on Monday.

"Unilateral abrogation or termination of the armistice agreement is not allowed under its regulations or according to international law," Foreign Ministry spokesman Cho Tai-Young told reporters.

Voiding the armistice theoretically paves the way for a resumption of hostilities, as the two Koreas never signed a formal peace treaty after the 1950-53 Korean conflict ended and remain technically at war.

Cho stressed that the ceasefire accord remained valid and that South Korea, in cooperation with China and the United States, would "resolutely" thwart any attempt by the North's to have it nullified.

"We demand North Korea withdraw remarks threatening stability and peace on the Korean peninsula and in the region," Cho added.

North Korea has declared the ceasefire dead or obsolete nearly a dozen times in the past 20 years.