An explosion from a torpedo likely sank a South Korean warship that went down near the tense border with North Korea last month, the South's defense minister said Sunday amid growing speculation Pyongyang may be behind the blast.
Defense Minister Kim Tae-young said the most likely cause of the disaster was a torpedo exploding near the ship, with the force of the underwater blast ripping the vessel apart. He did not speculate on who may have fired it.
Also Sunday, investigators who examined the front part of the ship said that a close-range, external explosion likely sank it.
Seoul has not directly blamed North Korea for the blast, but suspicion remains given the country's history of provocation and attacks on the South. Local media have increasingly been speculating the disaster was due to a North Korean attack.
The Cheonan was on a routine patrol on March 26 when the unexplained explosion split it in two in one of South Korea's worst naval disasters. At least 40 sailors died.
"Basically, I think the bubble jet effect caused by a heavy torpedo is the most likely cause" for the blast, Kim told reporters Sunday. Kim, however, said an investigation was ongoing and it's still too early to determine the cause.
Kim told lawmakers shortly after the blast that a North Korean torpedo or mine was among the suspected culprits. He said earlier this month that a torpedo attack was more likely.
Also Sunday, investigators said a preliminary investigation of the front part of the 1,200-ton ship — retrieved the day before — pointed to an external explosion.
Chief investigator Yoon Duk-yong told reporters the bubble jet effect likely sank the ship but stressed it's still too early to determine what caused the explosion.
The site of the sinking is near where the rival Koreas fought three times since 1999, most recently a November clash that left one North Korean soldier dead and three others wounded. The two Koreas have never signed a peace treaty since the 1950-53 Korean War ended in a truce.