The US is moving an advanced missile system to the Pacific island of Guam as a precaution following threats by North Korea, the Pentagon has said.
The Department of Defence said it would deploy the ballistic terminal high altitude area defence system (Thaad) in the coming weeks.
Pyongyang has threatened to target South Korea and the US in recent weeks.
The state’s warlike rhetoric follows new UN sanctions against North Korea and joint military drills by the US and South Korea.
The Thaad system includes a truck-mounted launcher, interceptor missiles, and AN/TPY-2 tracking radar, together with an integrated fire control system.
The Pentagon said the missile system would be moved to Guam, a US territory with a significant US military presence, as a “precautionary move to strengthen our regional defence posture against the North Korean regional ballistic missile threat”.
“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,” the Pentagon added.
The US had already planned to send a Thaad system to Guam, but not under these circumstances, analysts say.
Wednesday’s decision to expedite the transfer underlines how seriously Washington is taking Pyongyang’s threats, but it should be viewed as a purely defensive move, not an escalation, Riki Ellison, chairperson of the Missile Defence Advocacy Group, told the BBC.
He said the Thaad system would only protect Guam and the surrounding area, and would not cover South Korea or Japan.
In recent weeks, North Korea has mentioned military bases in the US territory of Guam and the US state of Hawaii as possible targets.
“Some of the actions they’ve taken over the last few weeks, present a real and clear danger,” said US Defence secretary Chuck Hagel, in his first major speech on Wednesday since taking up his post.
He added that Pyongyang had also threatened the interests of South Korea and Japan.
The North has apparently been angered by UN sanctions imposed after a recent nuclear test. Pyongyang has escalated its warlike rhetoric amid the current round of US-South Korea military drills.