MIAMI, JULY 6 -- It was a textbook example of Miami's ragged race relations: A fistfight between a shopkeeper and a customer over a pair of pants led to a confrontation Thursday between Miami police and more than 100 protesters outside the store.

The incident, a dispute between a Cuban merchant and his Haitian customer, blew up and laid bare a deeper rage. City officials felt compelled to contain the protest with nightstick-wielding police in riot gear.

As black leaders here today called for a federal investigation of the violent arrest of 58 Haitian protesters, leaders from Miami's ethnic groups and the Roman Catholic church met to discuss easing the racial tension that runs as an undercurrent through everyday life in South Florida.

"An exchange by a merchant of one race with a customer of another race should not have escalated into this kind of community reaction," said Lloyd Majors, assistant director of the Community Relations Board of Dade County, an organization charged with calming racial tensions among Miami's diverse ethnic groups.

"Underlying this situation is a longstanding anger toward the system for appointing the Cubans as the favorite immigrant," Majors continued. "While the Haitians are interdicted on the high seas, the Cubans are welcomed."

Miami's Haitian-American community, which numbers about 70,000, has grown increasingly militant over what its leaders consider abusive and discriminatory policies toward Haitian refugees. In April, a recommendation by federal Food and Drug Administration officials that because of a high incidence of AIDS Haitians be barred from donating blood prompted angry demonstrations by Haitian Americans here and elsewhere.

Miami's Haitians also staged demonstrations at the Immigration and Naturalization Service's detention center, where abuses against Haitian refugees were reported last spring by the Miami Herald. The majority of the detainees at the center are Haitians who entered the country illegally. Cuban refugees, who, like the Haitians, usually arrive by boat, are almost always granted political asylum and quickly released into the Cuban community.

"If they want a scapegoat, it is the Haitian," said Gerald Jean-Juste, director of the Haitian Refugee Center. "The Coast Guard interdicts only Haitians and only black refugees. We are the easy prey."

Thursday's confrontation had its roots in the visit of South African black leader Nelson Mandela last week. Miami was the only city of the eight Mandela visited to withhold an official welcome. Several Cuban-American city officials, including Mayor Xavier Suarez, denounced Mandela because of his statements supporting Cuban President Fidel Castro.

This snub to Mandela outraged blacks, many of whom regard Mandela as a heroic figure in the struggle for civil rights. For several days before he arrived, the dispute between Cuban and black leaders played out in the media, reopening old wounds.

When Mandela arrived June 28, Cuban demonstrators, carrying anti-Mandela signs, protested outside the hall where he spoke.

The next day, a Haitian named Abner Alezi went to pick up a pair of trousers he ordered altered at the Rapid Transit Factory Outlet, a clothing store in northeast Miami. The pants were not ready and Alezi argued with the store owner, Luis Reyes, and his 16-year-old son.

Police said they were not sure who threw the first punch. But word of the confrontation spread rapidly through Little Haiti after a Creole-language radio commentator urged members of the Haitian community to stand up for their fellow countryman.

Within minutes, a crowd that reached 200 began gathering in the parking lot outside the store. Miami police arrived a short time later. The demonstration ended peacefully and, to appease the crowd, police released three demonstrators who had been arrested.

Last Saturday, urged on again by disk jockeys, a crowd of 1,000 protesters gathered at the store, trapping the owner inside for six hours. But the ending again was peaceful.

Over the weekend, Cuban radio stations began a campaign of their own, criticizing city officials for not standing up to the Haitian crowd outside the Cuban-owned store.

By Monday, one of Miami's Cuban-American city commissioners, Miriam Alonso, sent a memo to city manager Cesar Odio, asking him to explain the police department's lack of "firm control."

When the store attempted to reopen Thursday, a crowd began to gather and police in riot gear, 160 strong, moved in quickly. City officials today defended their action, saying they had exercised great restraint for six days.

Of those arrested, 32 of the Haitian demonstrators were transported to the INS detention center to determine if they were in the U.S. illegally. All but seven were released today. The seven, who lacked proper legal papers, face possible deportation.