BBC: North Korea has ramped up rhetoric ahead of a UN vote on sanctions in response to its nuclear test.
Accusing the US of pushing to start a war, it vowed to exercise its right to launch a pre-emptive nuclear attack against its aggressors.
The Security Council meets later today to approve fresh sanctions against Pyongyang over the 12 February test.
Earlier this week, North Korea also threatened to scrap the 60-year truce which ended the Korean War.
"As long as the United States is willing to spark nuclear war our forces will exercise their right to a pre-emptive nuclear strike," said North Korea's foreign ministry, in a statement carried by the KCNA news agency, without giving further details.
The BBC's Lucy Williamson in Seoul says most analysts believe Pyongyang is unlikely to start a war with the US, and may instead be trying to provoke a fresh stance from Washington ahead of the UN vote.
But the atmosphere on the Korean Peninsula is more tense than usual, our correspondent adds, after North Korea said that it would tear up the armistice agreement next week.
The two Koreas remain technically at war in the wake of the 1950-53 Korean War, which ended with an armistice, not a formal peace treaty.
North Korea's military command said it would end that armistice on 11 March, threatening "surgical strikes" on its southern neighbour and the use of a "precision nuclear striking tool" in response to the sanctions and ongoing South Korea-US military drills. » | Thursday, March 07, 2013
