The South Korean Navy has deployed mine detector ships to search for any signs that the 1200-tonne warship ROKS Cheonan was sunk by North Korea.

Defence ministry spokesman Won Tae-jae said there were no abnormal activities by North Korean submersible craft or submarines in relation to this incident, according to straitstimes.com.

South Korea found no evidence regarding the involvement of North Korea in the incident, despite earlier speculating that a North Korean mine, either drifting or deliberately placed, might have caused the disaster.

A 60-member investigation team of military and civilian experts, including specialists in naval weaponry, explosives and shipbuilding engineering, are searching the area for possible shrapnel or parts of a torpedo or mine, according to a spokesman for the South Korean Joint Chiefs of Staff.