The United States failed in a planned missile defense flight test on Wednesday as the interceptor missile shut down on its launch pad in the central Pacific, local media reported.

The plan was for an interceptor missile to be fired from Kwajalein Atoll in the Marshall Islands into the path of a target missile launched from Kodiak Island, Alaska.

In a statement, the Pentagon's Missile Defense Agency said the interceptor was caused to shut down automatically in its silo at the Kwajalein Test Range by an unspecified anomaly.

The test, which was already delayed several times for bad weather and technical breakdown, was the first of its kind in two years.

The US Congress has appropriated over 10 billion dollars for the missile defense system for fiscal 2005, and the Missile Defense Agency estimated the system would cost as much as 53 billion dollars for 2004-2009.

After several successful intercepts since Bush's first election,the system failed to intercept a mock enemy missile in a test in December 2002.