A government source quoted by the South's Yonhap news agency said the North had assembled about 20 navy vessels including landing craft off the western port of Nampo and deployed MiG-21 fighters to Onchon airbase in the same area.

The Korea JoongAng Daily, also citing a government source, carried a similar report.

"It depends on the weather, but we believe they're setting up for a landing exercise sometime after Wednesday," Yonhap's source was quoted as saying.

Wednesday is the 58th anniversary of the signing of the armistice that ended the 1950-53 Korean War. The two countries are still technically at war, as no formal peace treaty was signed.

A defence ministry spokesman said he had no information on the reports, which came just four days after a rare meeting between nuclear envoys from the two Koreas raised hopes of an easing of tensions.

AFP