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 on Thursday to approve fresh sanctions against Pyongyang over the 12 February test.
North Korea's foreign ministry issued a statement carried by the KCNA news agency, without giving further details.
North Korea threatens nuclear strike, U.N. expands sanctions