BAENGNYEONG ISLAND, South Korea – Any navy crewmen still alive and trapped inside watertight cabins aboard a sunken South Korean ship would have just a few hours of oxygen left, military officials said Monday as divers plunged back into the Yellow Sea to find the wreckage.
Fifty-eight men, including the captain, were rescued in the hours after the Cheonan split apart late Friday and sank after suffering an explosion in the rear hull. Forty-six are missing and presumed trapped inside the ship, the Joint Chiefs of Staff said.
one of South Korea's worst naval disasters — remained unclear, and officials said it could take weeks to determine.
South Korean navy and coast guards ships and helicopters resumed the search for survivors after rough waves and high winds over the weekend prevented divers from getting underwater to access the wreckage near Baengnyeong Island in the west.
Four U.S. Navy ships and 16 divers joined the search Monday after getting a request from Seoul for assistance, said Lt. Anthony Falvo, a spokesman for the U.S. 7th Fleet, based just south of Tokyo.
The 1,200-ton Cheonan was on a routine patrol Friday night when an explosion tore a hole that split the ship apart within minutes, according to Capt. Choi Won-il.
There were initial concerns it was an attack from North Korea because the area has been the site of three bloody skirmishes in the past. The two Koreas remain in a state of war because their three-year conflict ended in a truce, not a peace treaty, in 1953.
However, North Korea did not appear to be involved, and the country's official news agency has made no mention of the ship. The North Korean military's first comments since the ship went down warned the U.S. and South Korea on Monday against engaging in "psychological warfare" by letting journalists into the Demilitarized Zone. It did not say anything about the sinking of the South Korean ship.
Still, the North Korean military was keeping a close watch on the search operation, the Joint Chiefs of Staffs said in a defense committee report cited by the Yonhap news agency.
President Lee Myung-bak, convening a security ministers Monday, urged authorities to focus on the rescue mission. The rescuers "should not give up hope," he said, according to the presidential Blue House.
Rear Adm. Lee Ki-sik of the Joint Chiefs of Staff said divers have located the rear segment, marked the spot with a buoy and were sending down underwater cameras.
"What our military considers most important is not salvaging the sunken ship but searching for the missing crew members," he said earlier. "We'll focus on searching for the crew and will salvage the ship after we locate everyone."
No bodies have been retrieved, feeding families' hopes that their sons and husbands might still be alive, the navy said. However, sonar devices used to locate the ship have captured no sounds coming from the sunken ship, naval officials said.
Most of the rescued crew members were in the front of the ship, while those missing were in the rear. The ship has dozens of waterproof cabins, and if crew members shut the doors quickly enough, some may still be alive, authorities said.
However, the oxygen supply would run out after 69 hours, giving them until 6 to 7 p.m. (0900 to 1000 GMT) Monday, they said.
Grief-stricken relatives boarded a boat Sunday to see the spot where the ship went down.
"My son said he would defend the nation, but instead he ended up like this," one cried out as she clutched a framed photo of her son.
Hyung-jin Kim reported from Seoul and Si-young Lee from Baengnyeong Island. Associated Press writers Sangwon Yoon in Seoul and Eric Talmadge in Tokyo also contributed to this report.