North Korea on Sunday accused US intelligence of staging a secret drill for a surprise attack on its nuclear facility and warned that an attack would trigger "horrifying nuclear disasters".

Rodong Sinmun, the North's ruling Workers Party newspaper, argued the United States was pushing ahead with "actual military actions that came in accordance with the second Korean war scenario of aggression."

"What merits a serious attention is that a special operation group of the CIA staged a secret drill to make a surprise attack on the nuclear facility of the DPRK (North Korea) and destroy it," it said.

"The US projected attack on the nuclear facility of the DPRK presupposes a nuclear war."

Tensions along the world's last remaining Cold War frontier escalated last week after Washington's announcement that North Korea had restarted a five-megawatt reactor capable of producing weapons-grade plutonium.

Rodong said its armed forces were ready to "mercilessly wipe out" a war of aggression.