South Korea's defense minister warned against premature conclusions over the sinking of the Cheonan warship after traces of explosives were found in the wreckage.

Defense Minister Kim Tae-young confirmed that government investigators found evidence of the powerful explosive RDX in parts of the raised hulk of the Cheonan.

But he asked that people be patient and wait for a forthcoming report on the fatal naval incident.

"Controversy sparked by groundless speculations could have a negative influence on our moves to deal with the incident after the investigation result comes out," Kim said. "This is a matter that should be approached based on objective facts."

He said there is no concrete evidence that the ship was the victim of a torpedo attack, as has been speculated.

"It is still premature to make any conclusion although the possibility of a torpedo is high. Please wait until the investigation team gives a detailed explanation," Kim said.

The results could be released as early as May 20, he said.

The 1,200-ton naval corvette Cheonan rapidly sank March 26 after an explosion strong enough to rip the vessel in half.

At the time of the sinking, Kim Tae-wook, a managing director at Hyundai Heavy Industries, said the ship's magazine might have exploded due to an "explosion from the outside."

The incident, which killed 46 South Korean sailors, immediately sparked speculation that the ship was struck by a North Korean torpedo. It sank just more than 1 mile southwest of Baeknyeong Island near the de facto sea border with North Korea.

But North Korea consistently denies it had anything to do with the sinking.

Kim ruled out a theory that the Cheonan struck a reef or collided with a U.S. vessel.

"As we explained during our interim report, the sonar system at the bottom of the ship remained intact and there were no scratches on the bottom of the ship, which are usually seen when a ship collides with a reef," Kim said.

Former South Korean navy Chief of Staff Adm. Song Young-moo, had earlier said that a torpedo and collision with a submarine is highly unlikely. The sea at around 80 feet deep is too shallow for a submarine and with currents too strong for smaller submersibles to operate.

The explosive material RDX also goes by the names cyclonite, hexogen and T4, and chemically is known as Cyclotrimethylenetrinitramine. It is used widely in military and industrial applications, often mixed with other explosives such as plasticizers, phlegmatizers or desensitizers to deadly effect.

Ahmed Ressam, the al-Qaida "millennium bomber," used a small quantity of RDX in the explosives that he prepared to bomb Los Angeles International Airport on New Year's Eve 1999.

RDX also was the main component used in the 2006 Mumbai train bombings and is believed to be the explosive in the Moscow metro bombings that killed nearly 40 people in March.

Kim was also cautious when talking about aluminum fragments found in sections of the splintered ship.

"There are some fragments that are part of the vessel and we are continuing to scrutinize them. It is not that easy for us to verify if what we have found is related to a torpedo or not," Kim said.