Police cordoned off a largely black neighborhood Tuesday after a six-hour melee of shooting, burning and rock-throwing that was touched off by the fatal shooting of a black motorcyclist by a white policeman.

Mayor Xavier Suarez declared the situation in the Overtown neighborhood under control Tuesday morning and called for an investigation.Police surrounded the neighborhood and allowed only those with legitimate business into the area, said a police spokesman, Officer Angelo Bitsis. Schools in the neighborhood were closed.

The riot erupted on the night of the federal holiday for slain civil rights leader Martin Luther King Jr. and as national attention was focused on the city as the host of Sunday's Super Bowl. It also rekindled memories of Miami riots in the early 1980s.

"It just exploded," said City Commissioner Rosario Kennedy as she prepared to enter the 11/2-square-mile area with a police escort. "People have been celebrating Martin Luther King's birthday all day. Maybe they were drunk. We just don't know."

The riot began about 8 p.m., about two hours after the death of motorcyclist Clement Lloyd. Lloyd, 21, was shot in the head as he was being chased for an alleged traffic violation, said Sgt. Michael Mazur, another police spokesman.

At least two officers were pursuing the motorcyclist for alleged erratic driving when they passed a third officer, William Lozano, who was stopped by the side of the road in an unrelated incident, police said.

Lozano, who is white, shot Lloyd as the motorcycle came toward him, said Assistant Police Chief Don March.

The motorcycle crashed into a moving car, injuring Lloyd's 24-year-old brother, who was a passenger on the cycle. The brother, whose name was not immediately released, was in critical condition Tuesday, according to Jackson Memorial Hospital officials.

Police said Lozano was temporarily taken off duty.

The Dade County Medical Examiner's office issued a statement Tuesday confirming that Lloyd was killed by the gunshot, not by the crash.

Within minutes of the shooting, at least 100 blacks began throwing rocks and bottles at police, who called for reinforcements. About 125 officers cordoned off the area, authorities said.

Four people, including one police officer, were treated for cuts and minor injuries, said Jackson Hospital spokesman Tony Fallon.

At one point, the Miami Herald reported, Suarez approached the crowd in an effort at conciliation but was driven back by rocks and bottles.

An auto parts store was burned to the ground after firefighters were shot at and had to leave the area, Mazur said.

During the height of the violence, tear gas was used to disperse some crowds, who attacked and burned several clearly marked news media cars.

WCIX-TV reporter Lourdes Ruiz-Toledo said she feared for her life.

"All of a sudden they threw a big huge rock right on the side of the driver. I blocked it with my elbow. They were yelling `Get that white woman out of the car!' " the 27-year-old reporter said.

Ruiz-Toledo, who had stayed in her car while two colleagues got out, said she drove a block and was rescued by an officer who led her from the car behind a plastic riot shield. The car was later burned.

A woman driving home from work said her windshield was shattered by a 5-pound concrete block.

"I had no idea it was going on," said Kay Worthington of Miami Beach. "There were about 20 kids all throwing things. I didn't see any cops around there."

Many blacks say they have been frustrated since Miami officials began providing free shelter for about 250 Nicaraguans seeking political asylum.

"They feel that other folks are being recognized and getting a piece of the pie but things are different for them. They feel they don't have nothing and what do they have to lose?" said Preston Marshall, who had organized a parade in King's honor that drew an estimated 100,000 people of all races in nearby Liberty City.

"Of all days, I didn't want this to happen," said Marshall, who was among black community leaders called in by city officials to help calm the crowd.

No damage estimates were available. Some looting and gunfire continued in Overtown early Tuesday.

During three days of rioting in Overtown in 1982, arsonists torched buildings and mobs broke into stores, causing millions of dollars of damage. The riot was sparked by the fatal shooting of a black man by a Cuban-born police officer.

The officer was acquitted of manslaughter charges in March 1984, sparking another disturbance that resulted in more than 200 arrests and several injuries. A police internal affairs report in 1985 concluded that the officer was justified in using deadly force.