Rally over NYC police acquittals in the death of Sean Bell
The decision to clear the officers was revealed yesterday.
Sean Bell, 23, died in a barrage of 50 police bullets as he left a strip club with two friends, hours before he was due to be married in November 2006.
Civil rights activist Al Sharpton told crowds in Harlem that the police had no right to shoot unarmed citizens.
He called for a campaign of civil disobedience to protest the verdict.
Mr Sharpton told the rally they would hold a meeting next week to plan the day when they would "close this city down".
Hundreds of people who packed the streetfront hall of his National Action Network offices chanted in response: "Shut it down!"
"We strategically know how to stop the city so people stand still and realise that you do not have the right to shoot down unarmed, innocent civilians," Mr Sharpton said.
"This city is going to deal with the blood of Sean Bell."
Mr Sharpton, who was joined by the dead man's family, said: "They never accused Sean Bell of doing anything. Then why is he dead?"
Criticising the verdict, Mr Bell's fiancee, Nicole Paultre Bell, said: "The justice system let me down... They killed Sean all over again. That's what it felt like to us."
She spoke out a day after storming out of the packed courtroom as the three officers - two of whom are black - were cleared.