South Korea has deployed rockets on two islands near its tense Yellow Sea border with North Korea to guard against possible attacks, reports said Monday.

The Chosun Ilbo newspaper, citing government sources, said more than 10 130-millimetre Kuryong multiple rocket launchers have been positioned on Yeonpyeong and Baengnyeong islands.

The North attacked Yeonpyeong with artillery and rockets last November, killing four people including two civilians and damaging dozens of buildings. Baengnyeong is the closest island to the North's coastline.

Each launcher has 36 rockets with a range of 23-36 kilometres (14-22 miles), Chosun said.

"This is the first time for us permanently to deploy multiple rocket launchers to the northwestern islands," it quoted a Seoul official as saying.

Yonhap news agency carried a similar report but did not specify the number of rocket launchers.

Cross-border tension has been high since the North's alleged torpedo attack on a Seoul warship that killed 46 sailors in the Yellow Sea in March 2010. Pyongyang has denied it was to blame for the sinking of the warship.

Since the island attack the South has been strengthening troop numbers and weapons on its five frontline islands near the disputed border.