A U.S. official says a missile interceptor failed to hit its target in a test conducted in Hawaii on Wednesday.
The official was not authorized to discuss the outcome and spoke on condition of anonymity.
The official said test data is being analyzed to determine why the interceptor, known as a Standard Missile 3 Block IIA, did not hit the target.
The failed test was first reported by CNN.
The Missile Defense Agency, which manages U.S. missile defense systems, issued a statement saying the interceptor was launched from the Pacific Missile Range Facility at Kauai, Hawaii, but did not reveal the outcome.
The interceptor is being developed in cooperation with Japan and is to be deployed on land as well as aboard ships.