CHICAGO (AP) - Thousands of nurses and other protesters gathered Friday at a downtown Chicago plaza for a noisy but largely peaceful demonstration demanding a "Robin Hood" tax on banks' financial transactions, before a smaller but more raucous crowd broke away and began marching through city streets.
The marchers chanted slogans and taunted police, who followed on bicycles and on foot. Police horses blocked some intersections as the breakaway groups wound through the city.
Friday's demonstrations were the largest yet ahead of a two-day NATO summit that is expected to draw even larger protests.
Members of National Nurses United, the nation's largest nurses union, were joined by members of the Occupy movement, unions and veterans. City officials have said the event could draw more than 5,000 because of a performance by former Rage Against the Machine guitarist Tom Morello, an activist who has played at many Occupy events. Early crowds did not appear to be that large.
The nurses and their supporters dressed in red shirts and wore green felt Robin Hood caps with red feathers. There were few problems at the rally, though police arrested at least one demonstrator as the gathering broke up.
About a dozen police officers, some wearing riot gear, surrounded the protester, who was dressed entirely in black and identified himself as a 19-year-old from Albuquerque, N.M. Police handcuffed him and walked him away from the rally on Daley Plaza.
Deb Holmes, a nurse at a hospital in Worcester, Mass., said she was advocating for the tax but also protesting proposals to cut back nurses' pensions.
"We've worked 30 years for them and don't want to get rid of them," she said.
The rally - which originally was scheduled to coincide with the start of the G-8 economic summit before that summit was moved from Chicago to Camp David - drew a broad spectrum of causes, from anti-war activists to Occupy protesters and Cathy Christeller's nonprofit Chicago Women's AIDS project.
Christeller, the agency's executive director, said there is common ground among all protesters, even against the backdrop of the NATO summit.
"The whole ... idea we should slash the (social) safety net instituted here and in Europe - It's a disaster," she said. "It ignores the source of the economic downturn, and it's making people suffer unnecessarily. This brings us together,"
Mary O'Sullivan and Chris Fogarty held the same signs that they carry every week. The retired couple have been protesting together for more than a decade, and Mary has carried the same sign for years, taping over "Honk to indict Bush" to read "Honk to indict banksters."
She said NATO "leaves rubble in their wake."
Ben Meyer, a Chicago lawyer who was observing the protest for the National Lawyers' Guild, denounced what he called an excessive police presence at the rally, which included dozens of officers milling through the crowd and lining the perimeter, some of whom were videotaping the rally.
"It's frustrating the state needs to come out and show this much force for a nurses' rally," he said. "They have everyone from the superintendent on down here. It's just ridiculous."
Chris Phillips, an Occupy activist from Buffalo, N.Y., said two police officers seized a wooden flag pole he was using to fly a flag reading "coexist" while standing on a bench on Daley Plaza. Officers told him the pole was considered a weapon.
"Did they read my flag? It's clearly a peaceful protest," he said. "I didn't hurt anybody. Are you kidding me?" Phillips said. He planned to protest nonstop for the next 4 days.
Meanwhile, lawyers for NATO summit protesters said police on Friday morning released four of nine activists arrested Wednesday on accusations that they had or planned to make Molotov cocktails.
The lawyers said police, with their guns drawn, raided an apartment building where activists were staying and arrested nine people. The Chicago chapter of the National Lawyers Guild said officers broke down doors in the building in the South Side Bridgeport neighborhood and produced no warrants.
The Chicago Police Department refused to comment.
Many office buildings in the usually bustling Loop business district were closed after workers were warned to stay home because of heightened security, snarled transportation and the possibility of unruly protests.
Other small protests, including one targeting climate change, are also planned.
Shawmaf Khubba, a student at Montclair State University in New Jersey, took a 14-hour bus ride on Thursday with 40 others to join the Chicago protests. He said he wanted to raise awareness and tough questions about what he called NATO's unwarranted military aggression around the world.
"NATO is a strong arm of the U.S. that gives an excuse to go everywhere around the world," he said before Friday's rally. "I'm here because I care about what happens to people around the world."
Scattered protests over the past week have been relatively small, including a march Thursday through the "Magnificent Mile" shopping district that drew about 100 people.
Estimates of how many might show up Sunday for an anti-NATO march have varied widely, from a couple of thousand to more than 10,000.
Police and the Secret Service have taken no chances as heads of state from 50 countries begin arriving for the NATO summit, where leaders will discuss the war in Afghanistan and European missile defense.
Security is high on trains. Barricades and fences have been erected around landmark buildings, and streets are being closed.