North Korea preparing for military exercise

North Korea appears to be preparing for a major military exercise amid continuing tensions on the Korean Peninsula.

A South Korean government official has been reported in local media saying preparations for a combined live-fire drill, with artillery units and air force jet, are under way near the western North Korean port of Nampo.

"It appears that the scale of the drill will be quite big," the unnamed official said.

The official was also quoted saying there were fears of military provocations or more missile test from the North during the exercise.

The North has been making threats to carry out missile strikes and nuclear war, after the United Nations imposed fresh sanctions over the North's third nuclear test in February.

Seoul and Washington have been on heightened alert over the past month in anticipation of an attack.

A South Korean military official was reported as saying the North may be trying to "fan military tension" after South Korea pulled out of the jointly-run Kaesong industrial park.

A North Korean attack on a South Korean island killed four people in November 2010, and Seoul believes Pyongyang is responsible for sinking one of its naval vessels the same year, killing 46 sailors.