WASHINGTON (AP) _ President Bush said he was sickened by the beating of a black motorist by Los Angeles police officers whose chief the president previously had hailed as an ''all-American hero.''

Bush continued to defend Chief Daryl Gates, a longtime political supporter the president has often cited as an exemplary crime fighter. But he said it would be up to Los Angeles officials to determine the chief's future.

The president and FBI Director William S. Sessions on Thursday denounced police brutality, vowing to pursue evidence that federal prosecutors could use to convict officers nationwide who use excessive and brutal force.

''Law enforcement officers cannot place themselves above the law that they are sworn to defend,'' the president said.

Bush also spoke forcefully about the Los Angeles beating incident, which has produced a growing chorus of demands for Gates' resignation. The March 3 beating of motorist Rodney King had been recorded on videotape by an onlooker.

''It was sickening to see the beating that was rendered,'' Bush said. ''There's no way in my view to explain that away. It's outrageous.''

But Bush declined to call for the ouster of Gates, who has been accused by critics of fostering an atmosphere that was tolerant of brutality.

Gates, a civil servant who cannot be removed without cause, ''is entitled to a credible hearing,'' Bush said. ''Nobody is going to prejudge anybody here.''

The president was asked if he thought Gates was responsible for the conduct of the officers who beat King. He said that was ''a matter, the way I see it, for the local police department.''

Bush praised Gates for his efforts to close down crack houses, saying ''in many ways he's been an exemplary police chief.''

But his praise was far less effusive than on March 5, when the president singled out Gates as one of ''the all-American heroes'' attending a meeting of law enforcement officials.

In a speech to the Justice Department's ''crime summit,'' Bush recalled how he had stood shoulder-to-shoulder with Gates in a poor neighborhood where officers had cleared out crack dealers.

That same day, national television networks began broadcasting a tape of the beating.

Four Los Angeles police officers have been indicted on state charges of assault with a deadly weapon for the beating, in which King was repeatedly hit with clubs and kicked.

The FBI is investigating whether all 15 officers at the scene of the beating can be charged with federal civil rights violations.

Bush made his comments Thursday before receiving a progress report on the investigation from Attorney General Dick Thornburgh.

''I was shocked by what I saw in that tape, that violence. To the degree there is a federal role here I am confident we will go the extra mile to see that is fulfilled,'' the president said.

Sessions, meanwhile, called on police chiefs across the country to make clear to their officers that ''we do not tolerate at all police brutality or the giving of summary punishment, because that is not the way we govern ourselves.''

Police chiefs must send a clear signal ''else what happens is you have a department that becomes accustomed to these types of things, and you must not have that,'' Sessions told reporters on Capitol Hill.

The FBI director declined to comment on the Los Angeles beating, but his comments appeared to be an indirect criticism of Gates.