Military officials say that a South Korean naval ship with 104 people onboard was sunk near the North Korean border today after an unexplained explosion in its stern.
South Korea's government called an emergency meeting but a presidential spokeswoman said it was still unclear whether the sinking resulted from a clash with North Korea.
The Joint Chiefs of Staff (JCS) in Seoul said that a South Korean naval vessel opened fire on an unidentified object earlier in the day, but it was later found to be a flock of birds.
The 1,200-ton vessel sank near Baengnyeong Island in the Yellow Sea. A rescue operation was underway.
A JCS spokesman said 58 crew members had so far been rescued.
The disputed border in the Yellow Sea was the scene of deadly naval clashes in 1999 and 2002.