By Lee Tae-hoon
Staff Reporter
A South Korean Navy patrol ship sank off the west coast at around 9:45 p.m. Friday near the disputed maritime border with North Korea, officials said.
As of 9:00 a.m. Saturday, 58 of the 104-crew members were rescued from the 1,200-ton ship Cheonan, but some 40 others were missing,
President Lee Myung-bak convened an emergency meeting, while the military deployed patrol boats and helicopters in a rescue operation.
The possibility of a North Korean attack was raised when local residents reported having heard "loud artillery firing" for at least 10 minutes from 11 p.m., according to Yonhap News.
Military officials were quoted as saying a South Korean vessel fired a shot northward at an unidentified ship, but the Joint Chiefs of Staff said the object caught on radar appears to have been a flock of birds.
"We have been unable to pinpoint the exact cause of the incident as of this moment," the Navy said.
Sources say an unexplained explosion in the rear of the ship may have ripped a hole in the vessel's bottom.
The United States said it had no evidence that North Korea had been involved in the tragic sinking.
"Let's not jump to conclusions here," State Department spokesman Philip Crowley said.
"I'm not aware of any evidence to that effect. But I think the authoritative source here would be the South Korean government."
The ship, which sank Saturday, was first deployed by the South Korean Navy in 1989, and was equipped with missiles and torpedoes, according to officials.
The incident comes amid increased tension between the two Koreas, which technically remain at war since the 1950-1953 Korean War ended in a truce, not a peace treaty.
North Korea has said in recent weeks it is bolstering its defense in response to joint annual South Korean-U.S. military drills that were held this month.
The disputed inter-Korean border in the West Sea was the scene of deadly naval clashes in 1999 and 2002.
leeth@koreatimes.co.kr