The White House said Thursday that President George W. Bush remains "firmly committed" to a missile defense system, even though the first full flight test of the system in two years failed.

"The president remains firmly committed to moving forward on missile defense," White House spokesman Scott McClellan said at a regular news briefing. "It's important that we move forward on this because the president's top responsibility is to do everything he can to protect the American people."

Bush's effort to deliver a key campaign promise by declaring a missile defense system operational by the end of this year suffered an embarrassing setback early Wednesday when an interceptor rocket failed to launch on cue in the first flight test in two years.

Sixteen minutes after a rocket carrying a mock warhead as a target was launched from Kodiak, Alaska, the ground-based interceptor experienced an anomaly shortly before it was to be launched from the Marshall Islands in the central Pacific Ocean.

The Pentagon is investigating what "unknown anomaly" caused an automatic shutdown of the interceptor.

The aborted test cast fresh doubt over the Pentagon's plan to activate a basic missile defense by the end of this month. The decision to declare the system operational had been expected earlier this year but was delayed after a series of canceled tests and developmental difficulties.

The Pentagon had conducted eight intercept tests of the system since 1999, the last on Dec. 12, 2002, and resulted in five hits.

Those tests, however, were conducted under controlled conditions.

The latest flight test incorporated for the first time the actual interceptor designed for the mission.

The failure would certainly renew a debate over the feasibility of a missile defense system, which costs 10 billion dollars a year.

Some lawmakers and military experts have criticized the Bush administration for rushing deployment on the basis of too few tests.

But the Pentagon has insisted that the decision to declare the system operational would be made independent of the outcome of the flight test.

At the White House news briefing, McClellan did not say whether Bush would further delay such a declaration after the test failure, but pointed to the previous test results instead.

"We have had five successful tests of the eight. And given the threats that we face in this day and age, missile defense is an important deterrent," he said.

Source:Xinhua