Anti-war activist Cindy Sheehan said Tuesday she was hurt slightly in a scuffle that erupted when police broke up a rally as she was at the microphone.
An organizer was arrested and charged with using a loudspeaker without a permit.
"I was speaking and someone grabbed my backpack and pulled me back pretty roughly," Sheehan said, describing the scene at Manhattan's Union Square on Monday. "I was shoved around."
Sheehan, the grieving mother whose vigil near President Bush's Texas ranch sparked anti-war protests around the country, said wasn't roughed up by police, but was jostled when officers broke up the rally and arrested organizer Paul Zulkowitz.
"I think their use of force was pretty excessive for someone that didn't have a permit," Sheehan said.
Paul Browne, spokesman for the New York Police Department, said Sheehan had finished speaking when officers arrested Zulkowitz, who had been repeatedly warned that he didn't have a permit, reports ABC.
According to IOL, the organiser, Paul Zulkowitz, was released after being given a court summons for charges of unauthorised use of a sound device and disorderly conduct, Detective Kevin Czartoryski told the Times, calling the arrest an "appropriate action".
But many onlookers were upset, with some saying the incident recalled the arrests of more than 1 800 protesters last year during the Republican National Convention.
"This is what's been happening for the last couple of years," said the co-chairperson of the Green Party's Manhattan chapter, Daniel Starling, who attended the rally.
"Every time we try to hold a demonstration, they arrest us."