“We will strengthen homeland missile defense by deploying 14 additional Ground-Based Interceptors (GBIs) at Fort Greely, Alaska,” Hagel said at a news briefing. “That will increase the number of deployed Ground Based Interceptors from 30 to 44, including the four GBIs at Vandenberg Air Force Base in California.”

The new missile interceptors are designed to shoot down long-range missiles in flight before they reach US territory.

Hagel cited North Korea’s latest nuclear weapons test in February and its development of long-range missile technology, including a mobile missile.

Last week North Korea threatened to launch a preemptive nuclear attack against Washington when the United Nations voted for new sanctions against North Korea in response to February’s nuclear test.

Hagel said the US is planning to deploy an additional radar in Japan to provide early warning and tracking of any missile launched from North Korea at the United States or Japan.

He also said that plans to bolster US missile defenses in the Pacific would not impact plans to cover all of Europe with a NATO missile shield by 2018.

“Let me emphasize the strong and continued commitment of the United States to NATO missile defense. That commitment remains ironclad,” Hagel said.