A weapon designed to blast nuclear missiles out of the sky has been tested at Vandenberg Air Force base but failed to hit its target.
The Missile Defense Agency says a ground-based interceptor missile was launched Friday. Its target: a missile launched 4,000 miles away from the Kwajalein Atoll in the Pacific Ocean.
The interceptor did not hit its target. Officials will try to determine the cause of any anomalies that may have prevented a successful intercept.
The interceptor is one of about 30 deployed in Alaska and at Vandenberg under a missile defense program begun in 2004.
In March, the Pentagon announced it will spend $1 billion to place another 14 interceptors in Alaska.
The military said it's responding to North Korean progress on nuclear weapons.