American Physical Society spokesman Robert Park said the failure of the Pentagon's 100-million-dollar test might lead President Bill Clinton to postpone a decision on deployment.

"I just don't see how, after a test like this, (Clinton) can declare that now it's going to be able to work, and call for deployment," said Park, who was formerly a researcher at the US government nuclear defense laboratory in Sandia, New Mexico.

Park noted that even if a missile shield could be made effective, it would do nothing to prevent less sophisticated methods of delivering nulcear or biological weapons, such as driving a truck across the US border.

However, he said, US aircraft manufacturer Boeing, the principal contractor for the project, has a strong financial interest in seeing deployment go ahead.

The missile test that failed Saturday had been intended to demonstrate that a missile-borne "kill vehicle" would not be confused by a decoy and would successfully seek out and destroy an incoming missile.

The test's failure raises pressure on Clinton, who leaves office in January, to defer to the next administration a decision on whether to order deployment.

George Bunn, a physics professor at Stanford University's Center for International Security and Cooperation, said the test's failure "certainly means there will be no decision to go full-blown ahead between now and the end of Clinton's term."

Bunn, who is a former official of the US Atomic Energy Commission and Nuclear Regulatory Commission and opposes deployment of the system, noted that under an April 1999 policy statute, the government may only proceed with the missile shield system if it is first demonstrated to be technologically feasible.

Sydney Drell, a Stanford University physicist who has served as an advisor to the White House on national security matters, said Saturday that any decision on deployment should not be hurried.

"There's a terrible danger in setting a schedule because someone says there's an immediate threat out there," he said.

"It's a difficult decision. One has to decide whether the threat is so real that one has to go ahead in spite of failure (in the test) on an accelerated course, or take some more conservative course" in which the results of successive tests set the pace.

If the United States went ahead with premature deployment in the face of opposition from Russia, China and also from European allies, it could prove counterproductive, he said.

"I am concerned at how we make a decision, and what political framework we preserve when we make a decision," Drell said.

He stressed that the course chosen should stay "consistent with our very extensive and profound and important efforts ... to reduce overall nuclear danger by preserving a regime of negotiations and treaties that we've been building on for 30 years."

Moreover, recent positive developments in North Korea, a country which the US has regarded as posing a threat, should be taken into account, he said.