The Rev. Al Sharpton and nearly 200 demonstrators were arrested Wednesday as they blocked traffic at the height of the evening rush hour to protest the acquittals of three detectives in the 50-bullet shooting of an unarmed black man.

Police estimated that about 190 people were arrested, including Sharpton, two survivors of the shooting and the slain man's fiancee. They lined up and peacefully put their hands behind their backs as police arrested them on disorderly conduct charges.

Sharpton, the two shooting survivors and Bell's fiancee were released from police custody about four hours later, said Sharpton's spokeswoman Rachel Noerdlinger.

The demonstrators prayed, sang and chanted such slogans as "no justice, no peace" as they converged on six heavily used bridges and tunnels. The protests were part of a coordinated campaign to urge federal authorities to charge the detectives with civil rights violations in the shooting of Sean Bell on his wedding day in November 2006.

The three officers were acquitted of state charges last month in a case that from the start ignited protests and spurred criticism of police tactics. One of the officers fired 31 shots, emptying his clip two times in a few short seconds.

Sharpton has said Wednesday's "pray-in" protest was a preview of potential future demonstrations designed to paralyze the city.

"We're going to keep coming until we get federal indictments. It's wrong," said Frank Rodriguez, a military veteran who brought a homemade model of the shooting scene to the Brooklyn Bridge rally, which began outside police headquarters in downtown Manhattan.

U.S. attorney spokesman Robert Nardoza said the case was under review, but he declined further comment about a possible federal case.

Sharpton, shooting survivors Joseph Guzman and Trent Benefield, and Bell's fiancee, Nicole Paultre Bell, linked arms as they blocked a street at the Brooklyn Bridge's base. They were trailed by at least 200 demonstrators who kneeled down in prayer in the road and counted from one to 50 in a stark reference to the barrage of gunfire that killed Bell. Some carried signs proclaiming, "We are all Sean Bell."

The protests were carefully orchestrated: Organizers circulated sign-up sheets for those willing to be arrested and issued instructions on how to behave when arrested. They also were advised not to volunteer if they had warrants out for their arrests or other pending legal issues.

The arrested protesters were expected to be issued tickets for misdemeanor offenses.

On the opposite side of lower Manhattan, an ethnically diverse crowd of about 80 demonstrators chanted, "We're fired up — we won't take it no more," and held hands as the Rev. James E. Booker Jr. blessed the crowd.

"Don't let Sean Bell's death be in vain," said Booker, pastor of St. John A.M.E. Church in Harlem.

After marching to the Holland Tunnel behind a "Stop the Brutality" banner, the protesters blocked two entrances to the tunnel as some sang the civil rights anthem "We Shall Overcome." Demonstrators who moved to the sidewalk applauded each time one of their fellow protesters was arrested.

Drivers waited patiently. "I disagree with doing anything illegal, but, hey, this is what makes America great," said Aaron Hanson, a passenger in a car waiting to get into the tunnel. "If this is what people really need to do to make a statement, it's what they should do."

A few miles uptown, some protesters were arrested after blocking traffic into midtown Manhattan on the Queensboro Bridge, while about 200 people rallied near the entrance to the Triborough Bridge in Harlem.

A heavy police presence initially stood by during the demonstrations, allowing the protesters to march unimpeded to the bridges and tunnels where they stopped traffic. Mayor Michael Bloomberg had pledged to "make sure that everybody's rights are protected and that the law is obeyed."

The racially polarizing case has raised questions about police use of deadly force in minority communities. Bell was black, as are two of his friends who were wounded in the shooting; the officers were black, Hispanic and white.

Bell crossed paths with the undercover detectives as he was leaving his bachelor party with friends.

The officers testified they feared for their lives after Bell and his friends got into a testy exchange with another patron and appeared to be going to retrieve a gun; Bell's friends testified the detectives fired wildly and without warning at Bell's car. No gun was ever found.

State Supreme Court Justice Arthur Cooperman, who heard the case after the detectives waived their right to a jury, said he found the testimony of the officers more credible than the version of events offered by the victims.

Police Commissioner Raymond Kelly said Wednesday that the police department was continuing to examine the possibility of disciplinary action against the detectives.