It is the latest in a series of delays that has halted flight testing of the system since December 2002 and pushed the next test beyond the November 2 presidential election.

The military still expects to move ahead with deployment of a rudimentary missile defense system in Alaska by the end of the year, Missile Defense Agency spokesman Rick Lehner said.

"There is no impact because this test isn't tied to beginning operations," said Lehner.

Air Force Lieutenant General Henry Obering, the MDA's director, decided to postpone the flight test on Friday because technicians had been unable to determine the root cause of an anomaly in a flight computer used to send back telemetry data during a test, he said.

Replacing the equipment involves sending the missile interceptor, which has been at a test site in Kwajalein Island in the Marshall Islands for months, back to the United States, according to Lehner.

Obering decided that since "there is no rush to do the test, it is best to take our time with this."

Flight tests, which involve firing the interceptor missile from Kwajalein island at a target missile launched from California, each cost an estimated 100 million dollars. The program has a 10 billion dollar budget this year.

Critics, however, have charged that the Pentagon is fielding the system without adequate testing.

The MDA has so far deployed two interceptor missiles at Fort Greely, Alaska and plans to deploy three more by the end of the year, allowing it to declare "initial operating capability."

Plans call for having up to 20 interceptor missiles at Fort Greely and Vandenberg Air Force Base in California by the end of 2005.

Since the malfunctioning equipment is test equipment, no changes have to made to the already deployed interceptor missiles, Lehner said.

All rights reserved. � 2005 Agence France-Presse. Sections of the information displayed on this page (dispatches, photographs, logos) are protected by intellectual property rights owned by Agence France-Presse. As a consequence, you may not copy, reproduce, modify, transmit, publish, display or in any way commercially exploit any of the content of this section without the prior written consent of Agence France-Presse.