A North Korean diplomat said Thursday that tensions on the Korean peninsula were running so high over the sinking of a South Korean warship that "war may break out at any moment."

In a speech to the international Conference on Disarmament, Ri Jang-Gon, deputy permanent representative for North Korea at the United Nations in Geneva, blamed the "grave situation" on South Korea and the United States.

"The present situation of the Korean peninsula is so grave that a war may break out at any moment," he said.

International investigators on May 20 announced their findings that a North Korean submarine had fired a heavy torpedo to sink the warship, in what has been described as the most serious act of aggression from the North since the Korean war 60 years ago.

Forty-six South Korean crew died when the warship sank near the disputed Yellow Sea border with the North in March in mysterious circumstances after a reported explosion.

South Korea has announced a series of reprisals including cutting off trade with its communist neighbor.

The North has denied involvement, and responded to the South's reprisals with threats of war.

Ri reiterated that North Korea had nothing to do with the sinking.

He claimed that North Koreans "were making their utmost efforts to attain the goal of a powerful and prosperous country by the year 2012" and needed a "peaceful environment" to do so.

"A peace treaty is the only successful and reasonable way for the denuclearisation of the Korean peninsula," he added.

The two countries have never reached a peace agreement since the 1950-53 war, relying on a tenuous Cold War era armistice.

However, he also warned that the North Korean people were "ready to promptly react to... various forms of tough measures including an all out war."

US Defense Secretary Robert Gates said on his way to an Asian security conference in Singapore that the United States and South Korea may hold additional military exercises in response to the alleged torpedoing of the ship.

Gates said there were no plans to deploy a US aircraft carrier as part of the exercises.

He was due to hold talks on the incident with his South Korean and Japanese counterparts.

In Geneva, the North Korean diplomat accused Seoul of trying to ignite a campaign against Pyongyang with an "anti-DPRK" policy intent on destroying exchanges and steps to reconciliation.

"The results of investigation made by South Korean regime is sheer fabrication based on assumptions guesses and supposition," said Ri.

South Korea's delegate retorted that the incident was a grave violation of the armistice agreement," adding that the evidence of an attack was "undeniable".

He said the statement in the UN's permanent arms control forum appeared to have been made "for propaganda purposes."