North Korea on Thursday denied that it was behind the attack on a South Korean warship that sank near their border in March, saying it would dispatch an “inspection group” to verify South Korea’s conclusion that Pyongyang is to blame.

The communist state’s National Defense Commission, of which North Korean leader Kim Jong-il is the chairman, said in a statement released through official television that any sanctions or retaliation over the sinking would be met with “tough measures including an all-out war.”

North Korea routinely warns of war for any act of punishment.

The North Korean reaction came about half an hour into a televised news conference in Seoul by a multinational team of investigators announcing “overwhelming evidence” that points to a high-performance North Korean torpedo for splitting the ship and killing 46 seamen.

“We had already warned the South Korean group of traitors not to make reckless remarks concerning the sinking of the warship Cheonan of the puppet Navy,” North Korea’s NDC said in a statement, according to the Korean Central News Agency.

“Nevertheless, the group of traitors has far-fetchedly tried to link the case with us without offering any material evidence.”

“It finally announced the results of the joint investigation based on a sheer fabrication,” the NDC said, calling the South Korean report part of a “smear campaign.”

“They are pointing a dirty accusing finger at us like a thief."

In response to a question during the new conference on whether Seoul plans to accept the group of investigators Pyongyang said it would send, Gen. Park Jung-yi replied that South Korea will follow the decisions made by the U.N. Command.

"As we are under an Armistice Agreement, the U.N. Command’s Military Armistice Commission will determine how the North was involved (in the sinking) and inform the North of its decisions," Park said.

Coinciding with the conference, the White House said it backs the South Korean conclusion and “strongly condemns” the March 26 attack on the 1,200-ton South Korean warship.

“We remind the group of traitors in advance that there should be not a shred of doubt about the material evidence to be produced before the inspection group,” the NDC said, warning of an “unlimited retaliatory blow, merciless strong physical blow” if South Korea responds with even a minor act of aggression on its territory.

South Korea plans to take the case to the U.N. Security Council. President Lee pledged Thursday to take resolute measures to make the communist regime “admit its wrongdoings through strong international cooperation.”

The Cheonan sinking is suspected to be a North Korean retaliation for a naval skirmish in November last year.

That month, a North Korean patrol boat opened fire on a South Korean naval ship after crossing the West Sea border. The ensuing battle forced the North Korean boat to retreat in flames.

The two sides collided in an exchange of gunfire twice before near the sea border in 1999 and 2002.

By Kim So-hyun (sophie@heraldcorp.com)