"It was a direct hit," said Chris Taylor, a spokesman for the Pentagon's Missile Defence Agency.

He says the interceptor missile was launched from Vandenberg Air Force Base in California 17 minutes after the target missile was launched from Kodiak Island in Alaska.

A "kill vehicle" deployed by the interceptor missile collided at 20:24 GMT with a mock warhead boosted into space by the target missile.

There have been 12 intercept tests since the start of the program, of which four were failures. © 2007 Australian Broadcasting Corporation