New York ? There were no televised scenes of protesters being beaten in the streets and no fire hoses aimed at people marching, but the question of whether city police violated the rights of protesters at the Republican National Convention in more subtle ways still lingers.

The New York Civil Liberties Union is compiling stories from protesters who say they were arrested for no reason, detained for unnecessarily long periods, or held in unsafe conditions. The group also is considering suing the city over police conduct.

Similar accusations resulted in lawsuits in Philadelphia after the 2000 Republican Convention there.

“We give the police a mixed grade,” said Civil Liberties Union Communications Director Sheila Stainback. “We recognize that the police did a great job with most events, particularly those with permits, but things kind of broke down when we got into events that weren’t permitted.”

Police and other city officials have denied any wrongdoing.

“The NYPD did a great job,” said Mayor Michael Bloomberg.

Police Commissioner Raymond Kelly said the 36,500 members of his force had performed “with restraint and professionalism.”

Police arrested 1,821 people, including several Lawrence anarchists, last week during convention protests that were often loud and angry.

Thousands swarmed Herald Square on Tuesday, shouting “GOP go home!” at delegates being shuttled to the convention in buses. About 1,200 of the week’s arrests happened that night. Police corralled people who were simply walking down the street so that they could not move, then arrested all of them, often without first ordering them to disperse and giving them a chance to do so.

Rohit Sharma said he was videotaping protesters Tuesday night when police ordered him and others to the sidewalk and slapped handcuffs on them.

“Basically, the police led us into an arrest,” Sharma, of New Brunswick, N.J., said. “Normally, they are supposed to tell people they will be arrested if they don’t disperse. They didn’t do that. That’s a huge civil rights violation.”

Sharma was charged with two counts of disorderly conduct, one count of resisting arrest, and a count of parading without a permit. He said he was held for 12 hours in “really, really filthy conditions” in a holding cage on Pier 57, a former bus terminal where police detained many protesters.

Many peace and civil rights activists contend that such arrests are part of a national pattern, evident since the chaotic protests against the World Trade Organization in Seattle in 1999, in which police illegally clamp down on dissent.

“They chill and they intimidate,” said Bill Dobbs, a spokesman for United for Peace and Justice, which organized last Sunday’s protest march, attended by several hundred thousand.

Civil rights lawyer Norman Siegel said the mass arrests were designed to stifle protests.

“What New York did this week would be like arresting the patriots before they ever got to the harbor during the Boston Tea Party, or arresting people before they ever sat down at the lunch counter. They’re doing what they call pre-emptive arrests.”