The ruling party newspaper, Rodong Sinmun, said North Korea was fully ready to "decisively control a preemptive nuclear attack with a strong retaliatory blow even if the US commits it any moment."

"Clear is the ulterior intention of the US talking about settlement of the nuclear issue through dialogue under the pretext of the six-party talks. In a word, it is to disarm the DPRK and stifle it with nukes," it said in a commentary monitored in South Korea.

The commentary came a day after the Stalinist country warned it would not dismantle its nuclear weapons until the United States delivered light-water reactors.

The North's fresh demand threw into doubt a hard-won deal at six-party talks in Beijing, in which the North pledged to give up its atomic weapons in return for energy and security guarantees.

North Korea "cannot remain indifferent towards the US attempt at a preemptive nuclear attack and will steadily strengthen its war deterrent to defend national sovereignty and security with supreme vigilance," Rodong said.