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.