The North's state-run Korean Central News Agency said that South Korean tanks were twice brought "to the verge of the military demarcation line (MDL)" in the middle of the demilitarized zone.

But the Joint Chiefs of Staff office in Seoul denied the North's claims, stressing its strict ban on military tanks and other heavy gear in the buffer zone which has divided the two Koreas since a war five decades ago.

"No tanks are allowed in the demilitarized zone. We stick to this rule," a Joint Chiefs of Staff spokesman said.

The North's news agency quoted military sources as saying that two South Korean tanks were brought to the verge of MDL markers "to uncover the tarpaulin and take a firing posture".

It said: "Such an act cannot be construed otherwise than a premeditated provocation of the South Korean military to escalate the inter-Korean military tensions."

The two Koreas have still been technically at war since the 1950-53 Korean conflict which ended in a fragile armistice rather than a peace treaty.

WAR.WIRE