SEOUL - North Korea warned Tuesday that South Korean-US war games this month would torpedo efforts to rid the peninsula of nuclear weapons, and vowed to strengthen its atomic arsenal if necessary.

The March 8-18 exercise comes "at a time when the international community is growing more vocal than ever before calling for a settlement of the nuclear issue", the official Korean Central News Agency (KCNA) said in a commentary.

"Obviously this is a deliberate attempt to disturb peace on the peninsula and torpedo the process for its denuclearization."

Diplomatic efforts are intensifying to revive six-nation nuclear disarmament negotiations after a break of almost a year.

"We are very anxious to see the talks resume, and we have made that clear to North Korea," US State Department spokesman Philip Crowley said Monday, a day after US envoy Stephen Bosworth ended a regional tour to try to restart the dialogue.

The North has set two conditions for returning to the long-running talks it abandoned last April, a month before staging a second nuclear test.

It calls for UN sanctions to be lifted and wants a US commitment to discuss a formal peace pact, replacing the armistice which ended the 1950-1953 war.

The North routinely criticizes war games in South Korea as a rehearsal for invasion, while Seoul and its ally Washington say they are purely defensive.

The Key Resolve/Foal Eagle exercise will draw 10,000 US troops stationed in South Korea plus 8,000 from abroad, and an undisclosed number of South Korean troops.

KCNA said such exercises would drive "the process for the denuclearization of the peninsula to a collapse".

"The reality goes to prove how urgent and crucial the conclusion of a peace treaty and the termination of the hostile relations are for finding a solution to the nuclear issue on the peninsula," it said.

Denuclearization "can never take even a step forward" as long as North Korea and the United States remain technically at war and the US threat of a nuclear conflict remains, it said.

"Should the US persist in its unrealistic moves to stifle (North Korea) in disregard of its realistic proposal, this will only compel it to boost its nuclear deterrent and its delivery means," KCNA said.

The North has said it developed nuclear weaponry because of a US threat of aggression and it cannot discard them while the threat remains.

Last week the military accused South Korean and US troops of planning a surprise attack under the pretext of their military exercises and warned it could respond with atomic weapons.