Mayor Tom Bradley finally came out and said what he's been hinting at for weeks - that Police Chief Daryl F. Gates should resign over the videotaped beating of a black motorist.

Gates refused.At a news conference Tuesday, Bradley appealed to Los Angeles' police chief of 13 years to step down, saying, "Chief Gates, now is the time for you to do the right thing for your officers, for your department, for the public you serve."

Gates has civil service protection and can be fired only by the Police Commission, a five-member civilian panel.

The 43-year veteran of the department called Bradley's plea a public relations stunt. Gates said he had a responsibility to lead the department through the furor over the March 3 beating of Rodney G. King.

"I don't believe that 8,300 police officers will follow the mayor anywhere," Gates said.

King, who had been pulled over for speeding, was beaten, kicked and shocked with a stun gun by police who did not realize they were being videotaped.

The videotape, which was broadcast nationwide, prompted assault charges against four officers and a federal investigation of police tactics nationwide. Civil rights activists across the country have clamored for Gates' resignation.

The American Civil Liberties Union said 20,000 people have signed petitions seeking Gates' departure.

Bradley had hinted the chief should step down - at one point saying the city's "healing process cannot begin as long as Daryl Gates is in office" - but never said so outright until Tuesday.

"I simply will not stand by as our city is split apart," the mayor said. "The damage to the department's reputation cannot continue."

Gates said he would step down only if the two citizen's panels investigating the beating - the mayor's Warren Christopher Commission and his own John Arguelles Commission - find he was derelict in his duties.