North Korea warned on Saturday that it would regard a move by Washington to bring a standoff over the North's nuclear program to the United Nations as a "prelude to war," and said it would respond with a "corresponding measure."
North Korea's official KCNA news agency did not say what the corresponding measure would be.
The communist country has been sharpening its anti-U.S. rhetoric amid tensions over its suspected nuclear weapons development.
The United States has proposed that the Security Council issue a statement denouncing North Korea's nuclear program. Washington and its allies have been pressuring the North to abandon its nuclear ambitions.
The North said it would consider the introduction of the nuclear issue at the U.N. Security Council "as a prelude to a war and take a corresponding measure."
The U.S. "intention to refer the issue to the U.N. can never be tolerated as it seeks to use the U.N. in achieving its criminal aim to isolate and stifle" North Korea, KCNA said.
Also Saturday, KCNA released a copy of a letter by North Korean Foreign Minister Paek Nam Sun sent to the Security Council, harshly criticizing the United States and urging the Council to take a neutral stance on the nuclear dispute.
"It can be said that now, the United Nations is at the crossroads of whether it will maintain the international order led by the United Nations or give way to the establishment of a dangerous world order led by an individual country," the letter said.
The Associated Press had obtained a copy of the letter Friday, submitted by North Korean Ambassador Pak Gil Yon.
North Korea accuses the United States of setting off the nuclear dispute to create an excuse to invade the communist country.
The nuclear standoff flared in October when U.S. officials said North Korea admitted having a secret nuclear program.
North Korea acknowledged for the first time on June 18 that it has a nuclear weapons program and warned it will strengthen it as a deterrent against being attacked. U.S. officials say North Korea has told them it already possesses nuclear bombs and plans to build more, but is willing to give them up in return for security guarantees and aid.
U.S. officials have said North Korea is believed to have at least one or two nuclear weapons. Since April, North Korea has claimed that it had all but completed reprocessing 8,000 spent nuclear fuel rods — a process that could yield several more bombs within months.
The United States and its allies suspended fuel shipments promised under the 1994 deal, and Pyongyang retaliated by expelling U.N. monitors, restarting frozen facilities capable of making nuclear bombs and withdrawing from the Nuclear Nonproliferation Treaty.
North Korea claims its moves are aimed at self-defense, prompted by the Bush administration listing it as part of an "axis of evil," erecting a missile defense aimed at stopping North Korean launched, and adopting a policy of preemptive war.
According to published reports, the North also wants nuclear weapons so it can whittle down its large and very expensive conventional force.
But many observers believe the economically isolated North, where famine is a perennial risk, is merely trying to squeeze more aid out of Western donors.