Hundreds of chanting demonstrators lined Manhattan's Fifth Avenue on Thursday, and dozens lay down in the street in a "die-in" to protest the war.

Officers, some in riot gear and on horseback, clamped plastic handcuffs onto about 150 protesters who refused to get up and half-carried them into police vehicles.

Anti-war groups also called for other civil disobedience in the city to protest media and corporate "profiteering from the war."

As helicopters hovered overhead, the protesters -- some beating drums or chanting "Hey-hey, ho-ho, Bush's war has to go!" -- jammed police pens near St. Patrick's Cathedral and the Saks Fifth Avenue store.

Organizers of the loose coalition, which calls itself M27, said the "die-in" was intended to symbolize Iraqi war victims. A single lane of Fifth Avenue was reopened to traffic after about a half-hour.

Later, a small group of protesters, draped in black and walking to the beat of a drum, staged a mock funeral march on the same block.

Organizers said roving groups of protesters also planned to jam intersections in other parts of midtown and lower Manhattan.

"Nothing else gets attention," said protester Johannah Westmacott, explaining the civil disobedience. "It's not news when people voice their opinions."

Russ Forster, a filmmaker from Chicago, said, "People are willing to risk life and limb, sitting in the middle of Fifth Avenue. I think that's a pretty strong statement."

The demonstration attracted several counterprotesters, including a man with a red, white and blue bandanna under a hardhat who argued toe-to-toe with a young protester with a pony tail and sideburns.

One counterprotester held a sign that read: "Traitors, have you forgotten Sept. 11?"

"Whether you're for or against it, we need to pull together," said Rachel Harary, 20. "Put on your flag and get them home."

Some protest signs were directed at the media. One protester held a sign showing a picture of parrots and the words, "Don't Parrot the Right-wing Propaganda."

Another, 44-year-old teacher Lee Whiting, held up a sign that said, "Embedded? or In Bed?" Embedded, she said, means "journalists are presenting almost exclusively the military view of this war."

Police and security officers placed a web of barricades at the adjacent Rockefeller Center, home of the GE Building, NBC and The Associated Press, to prevent the protesters from staging their "die-in" there.

On Wednesday, a similar but smaller protest had halted Fifth Avenue traffic for blocks.

The demonstrations are costing the city millions of dollars in police overtime, drawing resources away from crime-fighting and anti-terrorism operations, Police Commissioner Ray Kelly said Wednesday.

"This is more than protest, more than free speech," Kelly said. "We're talking about violating the law."

The traffic-blocking technique was used in recent protests in San Francisco, which led to thousands of arrests and complaints that police used excessive force.