"As we go through this transition, the Department of Defense remains prepared to address the threats that are posed by North Korea. And we will continue to be so. We have 28,500 troops on the Korean peninsula as we speak. They are ready to fight tonight. We have other capabilities in the region, again designed to protect the United States and our allies," he said.

Cook declined to discuss details of the North's missile activity, citing intelligence matters. He, however, reiterated that the US is ready to deal with the threat. He also urged the North to refrain from undertaking destabilizing acts.

The North may launch an ICBM from a mobile launcher at the Panghyon airfield in the northwestern part of the country. The failed Musudan intermediate-range ballistic missile was also launched from the same site last year, military officials in Seoul
said.    

The missile is believed to be equipped with the new engine that the North tested last April. The possible test-firing could provide valuable clues on what progress has been made by Pyongyang to launch a long-range missile and direct a warhead to its target, they said.

North Korean leader Kim Jong-un said in his New Year's Day address that the country has entered the final stage of preparation to test-fire an ICBM, a thinly veiled threat that Pyongyang is close to developing a nuclear-tipped missile capable of striking the continental US. 

In response, incoming US President Donald Trump has vowed to stop the North from mastering ICBM capabilities, saying Pyongyang's development of a missile capable of striking the US "won't happen."

US officials said the country is fully capable of defending itself and allies against North Korean missiles, with Defense Secretary Ash Carter saying the US would shoot down a missile if it were coming toward the US or allies.

Cook said the missile interception policy remains unchanged.

"That is the position of the US government and this Department of Defense and certainly this secretary of defense," he said. (Yonhap)