CHICAGO (Reuters) - Chicago police, who have a reputation for dealing toughly with protesters, will be prepared for the worst with new riot gear, including "sound cannon", if demonstrators at the NATO summit get out of line this weekend.
America's third-largest city and President Barack Obama's hometown has never hosted anything like the meeting starting on Sunday, which will draw representatives from some 50 countries, including leaders of the 28 members of the military alliance.
The two-day summit is also drawing protesters from around the United States and beyond, most to protest peacefully against the NATO-led war in Afghanistan and economic inequality.
Protest organizers hope thousands will turn out to demonstrate on Sunday and march to the summit site at a sprawling convention center along Lake Michigan.
Police said they will be keeping a watchful eye out for anarchists bent on more provocative actions, and have ordered about $1 million worth of new riot gear, including face shields that attach to helmets and fit over gas masks.
They have also ordered armor for police horses and acquired two long-range acoustic devices that can be used as "sound cannon" to disperse crowds.
Critics say these devices can cause hearing damage. A police spokeswoman said they would be used to deliver messages to crowds.
"What I want to do is extract the people who need to be extracted," Chicago Police Chief Garry McCarthy said of the strategy for handling protesters.
Police would not use their new riot gear unless it was necessary to control the crowds, he said in an interview broadcast on local radio on Tuesday.
There are fears are that the meeting could descend into the chaos of the 1999 World Trade Organization negotiations in Seattle, where window-smashing protesters ran wild. Since then, protests have become a fixture at such international meetings and police have become more sophisticated at handling them.
NATO's summit in the French city of Strasbourg in 2009 was marred by significant violence in which hundreds of youths rioted and set fire to buildings, although this was not repeated at the last meeting of alliance leaders in the Portuguese capital of Lisbon in November 2010.
There is also the ever-present risk of terrorism at such a gathering of world leaders, local FBI chief, Robert Grant, told a February briefing for business people.
"Weapons of mass destruction and all those things that scare people at night - that's my world," Grant said, adding that precautions were being taken to detect any plots.
Some Chicago city officials privately express the hope that Obama's decision to move the G8 summit -- a much smaller gathering of just the Western powers and Russia -- from Chicago to the seclusion of Camp David, Maryland, will diminish the protests as the G8 is where economic issues will be discussed.
Chicago police got a first taste of what may come on Monday and Tuesday.
On Monday, more than a hundred demonstrators tried to reach Obama's campaign office in a downtown high-rise to deliver a protest message and eight were arrested for refusing to leave.
On Tuesday, four protesters were arrested on when about 100 people opposed to U.S. immigration policy and anti-war protesters, staked out a courthouse in downtown Chicago.
Chicago Mayor Rahm Emanuel, Obama's former chief of staff, has taken a no-nonsense approach to protests in the past, pushing for new restrictions on demonstrations and sharply raising fines for violators, although he has softened some rules after civil rights groups criticized them as draconian.
However, while dozens of cities around the United States have allowed anti-Wall Street Occupy protesters to camp in downtown areas, Chicago barred a permanent encampment in a city park. Officers have been out in force, passively for the most part, at every sizeable demonstration, although there have been relatively few arrests.
Looking back in history, Chicago has a checkered record in its handling of protests, from the violent Haymarket worker riots of the 19th Century, to bloody clashes with anti-Vietnam War protesters during the 1968 Democratic Convention and Iraq war protests in 2003.
A former mayor, Richard J. Daley, often responded angrily to protests, issuing a "shoot to kill" order for any potential arsonist holding a Molotov cocktail during rioting after Martin Luther King's 1968 assassination.
A 2003 anti-Iraq war march ended badly when police cornered protesters and wouldn't let them leave for hours. Court rulings resulting from that episode led the city to agree to a costly settlement of some $10 million.
Jeffrey Cramer, a security expert with Kroll Inc and a former Chicago prosecutor, said that despite Chicago's history of tough policing, this was now "a different era where law enforcement professionals are in charge."
"What law enforcement is doing, and rightly so, is hoping for the best and preparing for the worst," he said. "There are those who are not going to be content with just holding a sign."
Many of the city's 12,000-strong police officers have undergone training in crowd control, a spokeswoman said, and a Chicago Fire Department captain said crews were learning how bring down protesters from bridges or other landmarks safely.
The city has done its best to cordon off the protesters from world leaders, forcing organizers of Sunday's march to move the gathering point further away from the convention center.
Protest leader Andy Thayer said he was disappointed that the U.S. Secret Service, which takes the lead role for security at such events, had drawn a security zone around the summit site that pushed demonstrators out of "sight and sound" of delegates.
The Secret Service ordered tall, metal fences that are both "non-scalable" and "resistant to thrown liquids" as part of the security zone several blocks around the summit site.
Two busy highways that pass next to the convention center, one of them Chicago's signature Lake Shore Drive, will be closed to traffic. No planes will be allowed and even yacht owners cannot moor their boats nearby, prompting one boat owner to ask for a discount on the city's $5,400 mooring fee.
Transportation bottlenecks are expected as police escort motorcades carrying NATO delegates around the city.
The mantra from city officials at frequent briefings has been that police will not interfere with protesters' right to demonstrate as long as the city's business is not disrupted. At the same time, a spokesman for local sheriff Tom Dart has stressed that there is plenty of room in the county jails.
The main risk, security experts said, is that so-called "BlackBloc" anarchists will wreak havoc.
A recent tweet posted on the Twitter site of #blackbloc, a shadowy anarchist group, said: "#blackbloc comrades, keep a low profile till u are forced 2 act. We do no 1 any good in jail all day."
Micah Philbrook, a spokesman for the Chicago Occupy movement, said the protesters were not planning any violence.
"The police are the ones armed to the teeth," he said. "We carry signs and beat drums."
Additional reporting by Emmett Berg in San Francisco; Editing by Greg McCune and David Brunnstrom