Three men accused of building Molotov cocktails were also planning attacks at President Obama's Chicago campaign headquarters and at the home of Chicago Mayor Rahm Emanuel during the NATO Summit, prosecutors said.
Brian Church, 20, of Ft. Lauderdale Fla., 24-year-old Vincent Betterly of Oakland Park, Fla., and 24-year-old Jared Chase of Keene, N.H. have all been arrested and charged with conspiracy to commit terrorism, providing support for terrorism and possession of an explosive or incendiary device.
"These men were here to hurt people," Cook County State's Attorney Anita Alvarez said in a news conference.
The defendants are self-proclaimed members of the "Black Bloc" group.
In addition to materials to make molotov cocktails, police say the defendants had various weapons, including a mortar gun, swords, a hunting bow, throwing stars, knives, brass knucles.
"This plot does not represent protest behavior, this is criminal behavior," said Chicago Police Superintendent Garry Mccarthy.
The men argue the materials police collected in an overnight raid Wednesday were used to brew beer.
Initially, nine men were taken into custody, six others have since been released.
Church, Betterly, and Chase, who are reportedly associated with the Occupy movement, say police are targeting them.
The National Lawyers Guild is representing the protesters.
Attorneys say a week ago the same three men were riding together in a car, when police pulled them over, questioned them, and then allowed them to continue with their day.
The men say they captured audio of the incident and posted it here on Youtube.
Many supporting the three charged men have taken to Twitter using the hashtag #NATO3.
All Eyes on Chicago
The arrests have contributed to an already tense environment as Chicago awaits the start of the NATO Summit. Thousands of protestors from across the country are already here for the international meeting which begins Sunday and ends Monday.
The Occupy movement, anarchists, anti-war supporters, environmentalists, and countless other groups are all competing to have their voices heard during the gathering of the world's most powerful leaders.
Months of planning and security preps will all be put to the test.
The stakes are high. This is President's Obama's hometown, and Mayor Rahm Emanuel just marked his first year in office.
Some 50 heads of state are expected to descend on the Windy City for the Summit.
With street closures, rerouting of public transportation, and the complete shut-down of a busy stretch of Lake Shore Drive, the conference will make getting around the nation's third largest city a nightmare.
Many of the 300,000 people who work in the downtown "loop" area have been told to work from home Friday and Monday. Those who do venture to the office have been told to ditch the business suits and dress casually, to avoid becoming targets of anti-corporate demonstrations.
Massive Security The U.S. Secret Service and F.B.I. have been in Chicago coordinating security efforts for at least the last two weeks.
Air Force F-16 jets are on alert to enforce flight restrictions over Chicago, and the U.S. Coast Guard is patrolling the waters of Lake Michigan with heavily armed vessels.
The Illinois National Guard and Illinois State Police will help shuttle motorcades to and from O'Hare Airport.
Sharp-shooters will be posted along the city's famed Michigan Avenue.
Bomb-sniffing dogs are on public transportation, and teams of officers on foot, and on bicycles, are scattered across the downtown area.
At a secret location in the suburbs outside Chicago, a Multi-Agency Communications Center—dubbed MACC-- has been created. Representatives from 43 federal, state, and local agencies will be in the same room to share real-time security information with each other.
Roger Goodes with the United States Secret Service says streamlined communication will be key should an emergency strike.
"For us in this room, we fear nothing. We think we are prepared to handle anything that comes up."
The Chicago Police Department is spearheading security on the ground.
All of the department's nearly 13,000 officers will be on the clock this weekend. Also, police officers from Milwaukee and Philadelphia have been called in for back-up.
Police Superintendent Garry Mccarthy says he wants to protect demonstrators' first amendment rights to protest, but safety will be paramount.
Police will be using high-tech countermeasures such as "sound cannons"—a device that can emit ear splitting sounds and messages to large crowds-- should protests threaten to get out of hand.
Authorities have also been consulting with police in Seattle, a city scarred after a World Trade Organization meeting in 1999 led to several days of violence there.
Superintendent Mccarthy is also trying a new approach. In an effort to not incite protestors, many officers will be in their everyday uniforms. Officers in full riot gear will be standing by and deployed when necessary.
Security expert Jeff Cramer, with Kroll Advisory Solutions, believes the months of training officers have undergone will go a long way to keep protests peaceful.
"The lessons that they have learned and the discretion of the police officers on the scene, that's what it comes down to. It's the police officer on the scene who is confronted with a protester, what does he or she do? And it's that discretion and training, that's what's going to determine how this weekend goes."
The security measures extend online as well, where cyber-police are working to block hackers before they strike. Authorities also say they are closely following Twitter and Facebook messages posted by protest groups, in hopes of stymieing off any threats before they become a reality.
The NATO Summit is supposed to bring almost $130 million in revenue to city coffers.
But for some business owners the conference will cost them money.
Fearing that protests could lead to riots and looting, some businesses have decided to keep their doors closed this weekend.
Rosa Yamada, who owns Designs by Rosa, a flower shop in downtown Chicago, will not be opening this weekend. The month of May is the middle of flower-selling season—peak time for graduations, weddings, and other ceremonies where flowers are a must.
Choosing to close this weekend was a tough decision, likely to cost her hundreds of dollars in business. Yamada fears street closures, and the uncertainty surrounding protests, will keep customers from coming in.
"In the 20 years that I've been in business, this will be the first Saturday—for the very first time—that we will be closing. I'm concerned for things going crazy."
Many businesses, including 22 Starbucks stores, have installed plastic film overlays to keep storefront windows from shattering.