South Korea mourns sailors

South Korean President Lee Myung-bak joined mourners on Monday to pay tribute to the 46 sailors who died after their warship sank following an explosion.

"The Republic of Korea will never forget your honourable sacrifice," Lee wrote in a condolence book.

The president laid a white chrysanthemum at an altar and bowed before portraits of the sailors.

The Cheonan was on a patrol when it sank March 26 in rough waters in the Yellow Sea. Forty bodies have been recovered, while another six sailors are missing and presumed dead. Fifty-eight sailors were rescued.

On Sunday, investigators said they had new information that indicates the force of a passing torpedo may have led to the sinking.

Defence Minister Kim Tae-young told reporters Sunday he believes a bubble jet effect is likely to blame. The term is used for the destructive column of water created after a torpedo is launched.

Yoon Duk-Yong, co-chair of the joint investigation team, said officials arrived at this conclusion following initial inspections of the wreckage and added the results are not yet definitive. However, he said there was no possibility of an internal explosion or a collision with the reef.

Kim said it would take up to a month before the joint investigation team comes out with its final report.

South Korea has stopped short of blaming North Korea for the loss of the warship, but remains suspicious of its neighbour.

The navies of North Korea and South Korea have clashed three times in the area of the explosion since 1999. The most recent clash was in November.