By THE ASSOCIATED PRESS
 
PORT-AU-PRINCE, Haiti, Oct. 1 (AP) - Violence erupted Friday in the Haitian capital, a day after three police officers were killed in a clash with protesters demanding the return of Jean-Bertrand Aristide, the ousted president.

Demonstrators who appeared to be Aristide supporters fired in the air, blocked a highway with burning tires and smashed car windows in the Martissant neighborhood of Port-au-Prince, witnesses said.

In the sprawling seaside slum of Cité Soleil, a gunman told a reporter that two street gangs loyal to Aristide were shooting it out, and one gang leader was killed overnight.

Several main roads in downtown Port-au-Prince were blocked by flaming barricades and piles of rocks. The usually bustling marketplace was empty.

"Everybody is afraid," said Fritz Jean, 43, who sells used televisions. "There's no security here."

Joanel Louis, a 30-year-old unemployed customs officer, said Aristide supporters ordered vendors to stay off the streets on Friday. "They told everybody to stay home," he said.

Tensions have exploded in Haiti as the country struggles to recover from floods caused by Tropical Storm Jeanne two weeks ago. The storm killed more than 1,550 people and left 900 missing, most of them presumed dead. Almost all the victims were in the northwestern city of Gonaïves.

The storm's aftermath has tied up some 750 of the 3,000 United Nations troops in Haiti.

Mr. Aristide's party, Lavalas Family, on Thursday began three days of commemoration of the coup in 1991 that unseated him the first time. It demanded an end to "the occupation" and "the invasion" by foreign troops - referring to the American-led force that followed Mr. Aristide's ouster in February and the United Nations peacekeeping troops who have taken over since June.

On Thursday, pro-Aristide demonstrators marching in Port-au-Prince shot and killed three police officers, and were believed to have kidnapped a fourth, Justice Minister Bernard Gousse said.

The violence erupted during a march by supporters of Mr. Aristide, now in exile in South Africa, to commemorate the 13th anniversary of his ouster in 1991 by the Haitian Army. Thousands of slum dwellers wound through downtown Port-au-Prince, chanting, "Like it or not, Aristide will return!" Protesters passed through a plaza in front of the National Palace and were a few blocks away when shots rang out.

Mr. Aristide has accused American agents of kidnapping him when he was flown out of Haiti on a American-chartered jet on Feb. 29. The United States insists that he left of his own free will.

Mr. Aristide, a former priest, became Haiti's first freely elected president in 1990. He was ousted within months by the army, restored to power by American troops in 1994, then forced to step down by United States pressure and a term limit. But he was re-elected in 2000.

In February, a street gang in Gonaïves known as the Cannibal Army rose up against Aristide, sparking a rebellion joined by soldiers from the army that Aristide disbanded in 1995.

American troops arrived as Mr. Aristide left but did little to disarm rebels, who are demanding the reinstatement of the army and have friendly relations with the American-installed interim government.

While violence flared in the capital, the hungry and some of the 200,000 homeless in Gonaïves were growing impatient with the slow pace of relief efforts. Hungry residents have repeatedly mobbed relief trucks and looted supplies.

The United Nations on Friday began an appeal for $32 million in aid for Haiti.