BY PETER WHORISKEY

 Tens of thousands of demonstrators are expected to converge on Little Havana today to protest the U.S. raid that returned Elian Gonzalez to his father.

 Police said they expected the event to be peaceful, but they were prepared for civil unrest, too.

 ``These events can and do come off without a hitch,'' said Lt. Rene Landa, who was coordinating police plans for the protest. ``The organizers have been very cooperative. The people they are asking to come are not trouble-makers. But we do have a contingent of officers on reserve -- in case of looting, shooting or fires.''

 Landa estimates a crowd of as many as 80,000.

 The demonstration comes just one week after anger over the federal raid on the Gonzalez home set off sporadic episodes of rock-throwing, tire-burning and traffic stoppages -- and led to more than 300 arrests. It also follows multiple, well-publicized allegations that the police used excessive force in quelling those disturbances.

 On Friday, as officers were preparing for the demonstration, Police Chief William O'Brien resigned, the culmination of political turmoil over the Elian case generated between Mayor Joe Carollo and City Manager Donald Warshaw.

 'MAINTAIN PEACE'

 ``We are going to do everything in our power to maintain peace and I think it will be peaceful,'' said Ramon Saul Sanchez, the leader of the Democracia Movement, one of the Cuban exile groups involved in the protest.

 Meanwhile, flyers have circulated calling for a counter rally in South Dade supporting the U.S. government. It would be at noon today at the corner of Southwest 107th Avenue and U.S. 1. Miami-Dade Police, however, have received no permit requests and organizers could not be identified.

 As the public divides, Lazaro Gonzalez, the great-uncle from whose home Elian was seized at gunpoint, released a statement calling for calm.

 UNCLE'S PLEA

 ``Elian is gone for now and my heart is broken,'' Gonzalez said. ``But South Florida must stay united. We cannot allow this tragedy to destroy our community.''

 Both sides tomorrow -- the police and the protesters -- will likely be wary of one another.

 Cuban-American protesters have complained that the police are too inclined to excessive force. In response, the City Commission on Thursday voted to create a task force to investigate the charges of unwarranted force.

 Meanwhile, some police officers said that the criticism could lead demonstrators to believe that they can defy the law.

 ``People will think they've been given the green light to do whatever they want out there,'' said Sgt. George Arias, echoing the comments of others. ``But if they do, they'll wind up in the back of a police car.''

 STREET CLOSED

 Beginning about noon today, Calle Ocho will be closed to traffic from Southwest 22nd to Fourth avenues. Buses also will be rerouted.

 Marchers are supposed to begin assembling about 1 p.m. on Calle Ocho near the Bay of Pigs monument, a memorial to an event that many Cuban Americans consider in the same light as the Elian Gonzalez raid: a betrayal by the federal  government.

 About 3:30 p.m., the protesters are supposed to march along Calle Ocho nine blocks east to Southwest Fourth Avenue, where a stage will be set up. According to the permit filed with police, demonstrators may carry hand-held signs only. Those signs must be flimsy -- no wood, metal or other solid supports are permitted.

 Speeches will follow the march.

 While others remarked on the potential for violence, Landa pointed to other Elian crowds that have been orderly. For example, he said, an estimated 20,000 people marched peacefully on Calle Ocho on March 29.

                     Copyright 2000 Miami Herald