North Korea on Saturday denied involvement in the sinking of a South Korean warship near their disputed border, a day after the South said an external blast was the most likely cause of the tragedy.

The statement was the first official reaction from Pyongyang after the 1,200-tonne corvette was broken in half in a mysterious blast on March 26, resulting in the loss of 46 lives, near the maritime border in the Yellow Sea.

"The war maniacs of the South's puppet military and rightwing conservative politicians are now making a foolish attempt to link the tragedy to us after having failed to find out the cause of the sinking," a statement carried by the North's official Korean Central News Agency (KCNA) said.

The statement, issued in the name of a military commentator, said South Korea was seeking to use the incident to shift the blame to the North and to justify its hardline policy towards Pyongyang.

"The reason that the South's puppets are claming the North's involvement is also linked to their foolish efforts to put pressure on us, even by stirring up international opinion in favor of sanctions (against the North)," it said.

South Korean Defence Minister Kim Tae-Young has raised the possibility that a mine or torpedo may have hit the Cheonan.

On Friday, he called for patience until a probe is completed but warned that the military would take "stern" action against whoever is found to be responsible.

Investigators said Friday that an external blast was the most likely cause of the sinking but Seoul has not yet officially put the blame on North Korea.

Yoon Duk-Yong, the co-head of a state investigation team, said that the steel plate of the warship's port side was curved inward, adding the warship seemed to have received a powerful impact from the port side.

Yoon dismissed the possibility of an onboard blast or a shipwreck.

He noted that no damage was done to the ammunition storage, fuel tank or diesel engine chamber and that there were no signs of fire, with wire insulation remaining intact.

The bottom of the ship was not grated either, an indication that the ship did not run aground, he said.

Analysts said the incident would have a negative impact on six-party talks on persuading North Korea to give up its nuclear arsenal.

US Assistant Secretary of State Kurt Campbell said Wednesday in Washington that two allies would have to agree on any next steps on restarting the talks.

The North quit the nuclear talks a year ago.

As preconditions for returning, it wants a US commitment to discuss a permanent peace treaty and the lifting of UN sanctions. Washington says it must first return to the nuclear forum and show seriousness about negotiating.

The disputed Yellow Sea border was the scene of deadly naval clashes between the North and South in 1999 and 2002 and of a firefight last November that left a North Korean patrol boat in flames.

earlier related report
Stern of stricken S.Korea ship moved to base for probe: navy
Seoul (AFP) April 18, 2010 - The stern of a South Korean warship that sank near the North Korean border leading to heightened North-South tensions was brought to a naval base south of Seoul on Sunday for further investigations.

On Saturday North Korea denied involvement in the March 26 sinking of the Cheonan, a 1,200-tonne corvette, with its official news agency issuing a vitriolic statement against the South.

Forty-six sailors lost their lives in the sinking and officials in the South said Friday an external blast had been the cause.

Seoul has launched an international investigation involving eight Americans, three Australians and four Swedes to ensure the eventual findings cannot be disputed.

Navy officials said Sunday the investigators were at the naval base in Pyeongtaek, 70 kilometres (43 miles) south of Seoul, looking into the stern which had been cleared of ammunition and was illuminated inside.

They were also scrutinising some 170 pieces of the debris for clues to the cause of the disaster.

While South Korea has not blamed the North for the sinking, Seoul's Foreign Minister Yu Myung-Hwan told KBS television on Sunday the UN Security Council could handle the case if Pyongyang is found to be involved.

Seoul's Defence Minister Kim Tae-Young has raised the possibility that a mine or torpedo may have hit the Cheonan, warning of "stern" actions against whoever is found to be responsible.

Yoon Duk-Yong, co-head of the joint state investigation team, said Friday the steel plate of the warship's port side was curved inward, adding the warship seemed to have received a powerful impact on the port side.

He ruled out an onboard blast or a shipwreck.

Analysts said the incident would harm diplomatic efforts aimed at persuading North Korea back to six-party nuclear disarmament talks that the communist state quit a year ago.

The Yellow Sea border was the scene of deadly naval clashes between the North and South in 1999 and 2002 and of a firefight last November that left a North Korean patrol boat in flames.

On Saturday the North's KCNA news agency said: "The war maniacs of the South's puppet military and right-wing conservative politicians are now making a foolish attempt to link the tragedy to us after having failed to find out the cause of the sinking.

"The reason that the South's puppets are claiming the North's involvement is also linked to their foolish efforts to put pressure on us, even by stirring up international opinion in favor of sanctions," KCNA said.