Officers encircled scores of demonstrators with orange netting during a protest near the former site of the World Trade Center. Detained protesters were loaded onto an off-duty city bus, and police put the count at about 200. The demonstrators insisted they were following police orders.
The protest's 500 demonstrators, a group called the War Resisters League, said they were staging a "death march" from Ground Zero to Madison Square Garden, site of the convention. The arrests happened about a block from Ground Zero.
An Associated Press photographer was detained briefly in the cordon before being released; a photo messenger working with the photographer was arrested and taken into custody.
Outside the Fox News Channel studios in midtown Manhattan, police in riot gear used barricades to contain around 1,000 demonstrators staging a "shut-up-athon" to denounce what they called the network's right-wing slant. One woman held up a sign that read: "Republicans are really stupid. They watch Fox News and believe it." Police said there were no arrests.
More than 800 people have been arrested in convention-related protest activity since late last week. On Tuesday, police also searched for a demonstrator who attacked a detective a day earlier.
On the third day of major protests, Manhattan began to resemble a crazy-quilt of barriers, heavily armed police and street-corner activists. The anti-GOP activism has been largely peaceful, with only a few exceptions.
"This is an uprising of the nonviolent variety of the people of New York and their allies across the country," said Shahid Buttar, 30, a lawyer from Washington, D.C.
Hundreds of protesters also massed on the steps of the New York Public Library for a planned march to the Garden. Verbal confrontations erupted as police moved them away from the library's front door, and at least 40 people were taken into custody. Organizers expected thousands of protesters as the march unfolded.
Police also announced the arrest of a 21-year-old Yale student after he entered a restricted area near Vice President Dick Cheney's booth at the convention Monday night, coming within 10 feet of him and shouting anti-war and anti-President Bush statements. Cheney was never in any danger, and no weapon was found on the man, authorities said.
Outside the midtown hotel where Texas delegates are staying, about two dozen protesters, depicting employees of "Hallibacon," grunted through plastic pig snouts Tuesday and wallowed in stacks of fake $100 bills bearing the images of Bush and Cheney.
The protesters accused Cheney and Halliburton, the company he once led, of profiting from the war in Iraq and its aftermath. They chanted: "We love money. We love war. We love Cheney even more."
Across the street from the Manhattan state Supreme Court building, a young man clad in black and wearing a Palestinian-style checkered scarf climbed a tree and was immediately ordered down by police.
As he descended, an officer grabbed his arm and pulled him away. The young man stood his ground, holding up his other hand and saying nothing. Other protesters rushed toward the police, shouting "Let him go!" The young man was hustled off.