The announcement out of North Korea came hours after US Defense Secretary Chuck Hagel ordered missile defense systems deployed to the western Pacific island of Guam, a US territory, and said the reclusive regime’s recent behavior presents a “real and clear danger.”

“The merciless operation of (our) revolutionary armed forces in this regard has been finally examined and ratified,” AFP cited the North Korean statement as saying.

The army statement added that war could erupt on the Korean peninsula “today or tomorrow,” AFP reported.

The Pentagon said earlier Wednesday that it will deploy a ballistic missile defense system known as a Terminal High Altitude Area Defense System (THAAD) to Guam in the coming weeks “as a precautionary move to strengthen our regional defense posture against the North Korean regional ballistic missile threat.”

“The United States continues to urge the North Korean leadership to cease provocative threats and choose the path of peace by complying with its international obligations,” the Pentagon statement said. “The United States remains vigilant in the face of North Korean provocations and stands ready to defend US territory, our allies, and our national interests.”

Speaking Wednesday at the National Defense University in Washington, Hagel said the North Koreans had “ratcheted up (their) bellicose, dangerous rhetoric–and some of the actions they've taken over the last few weeks present a real and clear danger and threat to the interests, certainly of our allies, starting with South Korea and Japan,” Fox News reported.

White House spokesman Jay Carney said Wednesday that Washington is continuing “to monitor the situation” on the Korean peninsula.

“The provocative actions and bellicose rhetoric that we see from North Korea is obviously of concern, and we take—are taking the necessary precautionary measures,” Carney told reporters, adding that Pyongyang’s behavior “represents a familiar pattern.”

The statement Wednesday by the North Korean army follows a pledge by Pyongyang on Tuesday to restart facilities at its Yongbyon nuclear complex, including a uranium enrichment plant and a reactor.

Tensions began to rise on the Korean Peninsula after international sanctions were imposed on North Korea in response to a long-range rocket launch in December that world powers condemned as a ballistic missile test. North Korea responded by carrying out a third nuclear test in February, which was followed by more sanctions.

North Korea has threatened pre-emptive nuclear strikes on the US mainland and US military bases in the region.