It isn't clear what caused the sinking.
Reuters reports the ship is carrying 100 sailors and that the North was bolstering its defenses after the South Koreans and US held joint drills earlier in the month.
That comes on the heels of a statement warning that the North would use its nuclear capabilities after learning of a report on the South Koreans and US preparing for possible instability following the demise of the North Korean regime.
"Those who seek to bring down the system in the (North), whether they play a main role or a passive role, will fall victim to the unprecedented nuclear strikes of the invincible army," North Korea's military said in comments carried by the official Korean Central News Agency.UPDATE:
Yonhap news is reporting the following:
1,500-ton ship carrying 104 crew members went down around 9:45 p.m. near a South Korean island in the Yellow Sea, prompting an emergency meeting of security-related Cabinet ministers.It also reports that the ship that was sinking had fired at an unidentified ship to a position north of where the ship sank.
Seoul's Navy officials refused to give details, but said a South Korean vessel fired at a ship toward the North later in the evening, indicating possibilities of a possible torpedo attack from the North. Local residents reported having heard gunfire for about 10 minutes from 11 p.m.
"The ship appears to have begun sinking after an explosion at the rear of the ship," the Navy said in a statement. "We have been unable to find the exact cause of the incident as of this moment."
The Navy said it has rescued 58 crew members during an ongoing rescue operation, but fears some may have died.
At least 46 South Korean navy personnel aren't accounted for according to the BBC. This isn't the first time the two Koreas have had border skirmishes or their navies exchanged fire, but it is the most serious incident in recent years.
2009: One North Korean sailor killed in a naval battleRight now, there's speculation that this was a North Korean torpedo responsible for the incident, but there's no confirmation one way or the other. It could have been a mine as these waters are heavily mined by the North Koreans to keep the South away.
2002: Four South Korean sailors and an estimated 30 North Koreans killed in a naval battle
1999: At least 17 North Korean sailors believed killed in naval fire fight
1998: South Korea captures a North Korean mini-submarine in its waters
1996: A North Korean submarine runs aground in South Korean waters
China's biggest trading partner is the US - they aren't going to mess that relationship up over North Korea unlike the situation in the runup to the Korean War. China has quite a bit to lose with the North Koreans agitating for conflict. China is North Korea's biggest trading partner and isn't likely to let their militaristic and incomparably totalitarian neighbor drag it into a conflict with the US and South Korea, so expect them to exert whatever pressure they have on the North Korean regime to get this under control. The Chinese will want to prevent a mass exodus of refugees from the North. But just how much leverage the Chinese have over the regime in Pyongyang is uncertain.
The South Koreans are downplaying the incident and reported that satellite information doesn't indicate a North Korean presence in the area.