The US has said it will deploy a missile defence system on the US Pacific territory of Guam to strengthen the region's protections against a possible North Korean attack.
The delivery of the missile shield system comes as Chuck Hagel, US defence secretary, labelled North Korea's recent rhetoric as a real, clear danger and threat to the US and its Asia-Pacific allies.
He added that the US is doing all it can to defuse the situation.
Deployment of the Terminal High Altitude Area Defence System is the latest step the US has taken to bolster forces in the region in a far-reaching show of force aimed at countering the North Korean threat.
The Pentagon already has sent dispatched bombers, stealth fighters and ships.
Tensions have escalated between North and South Korea in recent weeks. The communist North has vowed to increase production of nuclear weapons materials, and threatened a pre-emptive strike against the US.
Hagel told an audience at the National Defence University that there is a path to peace on the troubled Korean peninsula, but it doesn't include making nuclear threats or taking provocative actions.
The land-based missile defence system includes a truck-mounted launcher, tracking radar, interceptor missiles, and an integrated fire control system.
The Pentagon said the system will boost defences for American citizens in Guam, a US territory, and US forces stationed there.