In a slow, somber procession, several thousand demonstrators conducted a silent march on Sunday down Fifth Avenue to protest the New York Police Department’s stop-and-frisk policies, which the organizers say single out minority groups and create an atmosphere of martial law for the city’s black and Latino residents.

Two and a half hours after it began, the peaceful, disciplined march ended in mild disarray. As many marchers dispersed, police officers at 77th Street and Fifth Avenue began pushing a crowd that defied orders to leave the intersection, shoving some to the ground and forcing the protesters to a sidewalk, where they were corralled behind metal barricades. After protesters pushed back, the officers used an orange net to clear the sidewalk, and appeared to arrest at least three people.

The presence of several elected officials at the march, including the Democratic mayoral hopefuls Bill de Blasio, the public advocate; Christine C. Quinn, the City Council speaker; Scott M. Stringer, the Manhattan borough president; and William C. Thompson, the former city comptroller, seemed to signal a solidifying opposition to the policy, which has long been opposed by civil rights groups.

Wade Cummings, 46, a teacher, attended with his 19-year-old son, Tarik. Both said they had been stopped by police officers — once for the father, three times for the son.