SEOUL: North Korea warned the South yesterday to cancel an artillery drill planned to begin as early as today that it said would provoke stronger retaliation than shelling last month that killed four people.

Retaliation would be "deadlier" than on November 23, the Korean Central News Agency said. That barrage of Yeonpyeong Island killed two civilians and two soldiers, shattered the windows of a school during classes, set 30 houses on fire and burned 25 hectares of land.

A US State Department spokesman, Philip Crowley, said the planned exercise "is a perfectly legitimate step" by South Korea.

It would go ahead some time between today and Tuesday as planned, said a spokesman for South Korea's Joint Chiefs of Staff. About 20 US military personnel will be sent to the island to assist.

A warning for civilian ships was posted yesterday on the website of the Korea Hydrographic and Oceanographic Administration.

North Korea does not recognise the western sea border demarcated by the United Nations after the Korean War, and demands that it should be drawn further south to include Yeonpyeong and neighbouring islands in North Korean waters.

The South Korean Defence Minister, Kim Kwan-jin, said earlier this month that South Korean retaliation against any further attack from North Korea would include air strikes.

Bloomberg