SEOUL, South Korea -- North Korea, accused of waging the deadliest attack on the South Korean military since the Korean War, flatly denied sinking a warship Thursday and warned that retaliation would mean "all-out war."
Evidence presented Thursday to prove North Korea fired a torpedo that sank a South Korean ship was fabricated by Seoul, North Korean naval spokesman Col. Pak In Ho told broadcaster APTN in an exclusive interview in Pyongyang.
He warned that any move to sanction or strike North Korea would be met with force.
"If [South Korea] tries to deal any retaliation or punishment, or if they try sanctions or a strike on us ... we will answer to this with all-out war," he told APTN.
An international team of civilian and military investigators declared earlier in Seoul that a North Korean submarine fired a homing torpedo at the Cheonan on March 26, ripping the 1,200-ton ship in two.
Fifty-eight sailors were rescued, but 46 died -- South Korea's worst military disaster since a truce ended the three-year Korean War in 1953.
President Lee Myung-bak vowed to take "resolute countermeasures" and called an emergency security meeting for Friday.
The White House called the sinking an unacceptable "act of aggression" that violated international law and the 1953 truce. U.S. troops in and around South Korea remained on the same level of alert, said Adm. Mike Mullen, chairman of the Joint Chiefs of Staff.
U.S. State Department officials reacted cautiously Thursday, refusing to call the attack an act of war or state-sponsored terror. The Obama administration's tempered response was an indication of how few options President Barack Obama has and how volatile the situation is.
"There's no interest in seeing the Korean peninsula explode," said P.J. Crowley, U.S. State Department spokesman.
Japanese Prime Minister Yukio Hatoyama declared his support for South Korea, calling North Korea's actions "inexcusable."
However, South Korea's options for retaliation are limited.
The armistice prevents Seoul from waging a unilateral military attack, and South Korea would not risk any retaliation that could lead to war, said North Korea expert Yoo Ho-yeol at Korea University in Seoul.
"That could lead to a completely uncontrollable situation," he said, noting that Seoul and its 10 million residents are within striking range of North Korea's forward-deployed artillery.
South Korea and the U.S., which has 28,500 troops on the peninsula, could hold another round of joint military exercises in a show of force, said Daniel Pinkston, a Seoul-based analyst for the International Crisis Group think tank.
He also said the military will likely improve its early warning surveillance abilities and anti-submarine warfare capabilities to prevent such surprise attacks in the future.
Analysts said Seoul could move to punish North Korea financially, and Foreign Minister Yu Myung-hwan also has said Seoul would consider taking it to the U.N. Security Council. However, the matter did not arise Thursday during a Security Council meeting on Sudan, several ambassadors said afterward.
The impoverished country is already suffering from U.N. sanctions tightened last year in the wake of widely condemned nuclear and missile tests.
Any new Security Council action would require backing from permanent seat holder China, but analyst Koh Yu-hwan at Seoul's Dongguk University said Beijing, North Korea's traditional ally and backer during the Korean War, was unlikely to accept the Cheonan investigation report.
China responded mildly to the report, with Vice Foreign Minister Cui Tiankai calling the sinking "unfortunate" and reiterating the need to maintain peace on the Korean peninsula.
North Korea is accused of waging a slew of attacks on South Korea over the years, including the 1987 downing of a South Korean airliner that killed all 115 people on board. It has never owned up to the attacks, and Seoul has never retaliated militarily.
Since the signing of a nonaggression pact in 1991, clashes between the North and South have focused on the waters off their west coast.
North Korea disputes the maritime border drawn unilaterally by U.N. forces at the close of the Korean War, and the area where the Cheonan sank has been the site of several deadly naval clashes, most recently in November.
Pak, the North Korean naval official, said his country had no reason to sink the Cheonan.
"Our Korean People's Army was not founded for the purpose of attacking others. We have no intention of striking others first," he told APTN. "Why would we attack a ship like the Cheonan, which has no relation with us? We have no need to strike it, and doing so would have no meaning for us."
Investigators from the five-nation team said detailed scientific analysis of the wreckage, as well as fragments recovered from the waters where the Cheonan went down, point to North Korean involvement.
Torpedo fragments found on the seabed "perfectly match" the schematics of a North Korean-made torpedo Pyongyang has tried to sell abroad, chief investigator Yoon Duk-yong said. A serial number on one piece is consistent with markings from a North Korean torpedo that Seoul obtained years earlier, he said.
"The evidence points overwhelmingly to the conclusion that the torpedo was fired by a North Korean submarine," he said. "There is no other plausible explanation."
Pak, the North Korean military official, dismissed it as faked evidence.
"If there were indications that the sinking was our doing, then the whole thing is an act -- theatrics by the South Koreans to implicate us," he said.
The colonel spoke to APTN outside another foreign warship: the USS Pueblo, seized by North Korea in a high-seas hijacking in 1968. The American captain and crew were held for 11 months before being freed.
Towed to Pyongyang in 1999, the ship is popular tourist sight, a floating museum moored along the Taedong River that showcases North Korea's naval exploits.
Pak, a 55-year veteran whose uniform was bedecked with medals, said he was among those who helped capture the USS Pueblo more than four decades ago.
Associated Press writers Kelly Olsen, Sangwon Yoon and Hyung-jin Kim in Seoul, Jay Alabaster in Tokyo, Chi-Chi Zhang in Beijing, Anne Flaherty and Matthew Lee in Washington, and Edith M. Lederer at the United Nations contributed to this report.