SEOUL: Ships and aircraft today searched choppy and frigid seas for survivors of one of South Korea’s worst naval disasters, but hopes faded for 46 missing after an unexplained explosion tore a warship in half.

The tragedy happened near the tense disputed Yellow Sea border with North Korea, scene of bloody naval clashes in 1999 and 2002. Seoul officials said there was no sign so far the North was to blame.

President Lee Myung-Bak called emergency security meetings and ordered a swift and thorough probe into the sinking yesterday evening of the 1,200-tonne corvette near Baengnyeong island.

Details of the disaster began to emerge today.

“The ship was torn apart and the stern sank immediately,” Choi Won-Il, captain of the Cheonan, told relatives of those missing.

“While I was reviewing an operation plan in my cabin, there was the sound of an explosion and the ship keeled to the right. We lost power and telecommunications,” Yonhap news agency quoted him as saying.

“I was trapped in the cabin for five minutes before my colleagues broke the window in and let me out. When I got out, the stern had disappeared.” The Joint Chief of Staff (JCS) said 58 sailors had been rescued but 46 were still missing as of this evening. Thirteen of those saved were injured but in stable condition.

“Many of the missing people might have been trapped inside the sunken ship,” JCS spokesman Lee Ki-Sik told a parliamentary committee. A team of 18 navy divers had to postpone an attempt to search the upturned craft until tomorrow because of high waves and darkness. Defence Minister Kim Tae-Young said thermal images indicated the ship had been torn in half. “But we have to pull her up to determine the exact cause,” he said, adding a salvage ship would arrive tomorrow afternoon.

Reports said the 88-metre craft would have been carrying missiles, torpedos and other weaponry and munitions. However survivors believe the impact came from outside, according to defence ministry spokesman Won Tae-Jae.

“The possibility of the ship having been attacked will be investigated,” Won said.