Chicago Police Superintendent Garry McCarthy says Sunday's protests resulted in 45 people being arrested and four officers suffering injuries -- one from a stab wound in the leg.
McCarthy got emotional when talking to reporters about his officers' performance Sunday night. "Those guys were amazing," said McCarthy.
Also late Sunday, Mayor Rahm Emanuel released a statement about Sunday's protests, saying, "Today's march was peaceful with approximately 2,000 people exercising their First Amendment rights. While there have been some scuffles with individual protesters, the Chicago Police Department has acted professionally and with restraint as protesters refused to disperse."
Security Expert: Black Bloc intent on creating conflict
A group of protesters dressed all in black and believed to be part of the Black Bloc threw items at officers and hit them with sticks during the afternoon skirmish. Police officers used batons to respond. At least two injured protesters were treated by volunteer medics on the scene.
Chicago Police Superintendent Garry McCarthy was spotted in the middle of the melee. He was behind officers in full riot gear. Those officers -- and the mounted patrol-- were called in to disperse the crowd after the march and rally had ended.
The melee came after a relatively peaceful anti-NATO afternoon rally and march. Officials say the Black Bloc is a group of protesters that attend events around the world creating civil disobedience. Earlier Sunday, seven people dressed in black were arrested for allegedly having items that could be used as weapons.
"You have classic Black Bloc ideology, peaceful ceremony, moving ceremony and these individuals use this as an occasion to disrupt, engage the police, engage in criminal activity. Once they crossed that behind and are throwing bribes at the police officers and hitting them with sticks and weapons then they have no option but to maintain control. It is classic Black Bloc ideology. It ruins ceremonies and ruins a ceremony of veterans turning in their valor medals," former Chicago police superintendent/ABC7 security expert Jody Weis said Sunday.
The Black Bloc was also believed to be involved in another incident that took place during the march, an Associated Press report indicated that police and protesters clashed during the middle of the parade. The protesters, dressed in black, allegedly surged toward police and threw objects at officers. Police fought back with batons.
Those protesters ran away, but reconvened with the main crowd near the parade's end at Cermak and Michigan Avenue and are believed to be part of the later clash with police, who beefed up security around that area -- and officers showed up in full riot gear.
Officials also brought in the LRAD, which stands for Long Range Acoustic Device. The device projects sound in a 30-degree cone and has messages like, "This is the Chicago Police Department, please continue to disperse to the west." The LRAD made announcements in English and Spanish.
Later Sunday night, hundreds of protesters gathered outside of the Art Institute of Chicago where first lady Michelle Obama was hosting a dinner for spouses of NATO leaders. At least 100 Chicago police officers were on the scene in riot gear, wearing helmets and holding batons.
Police say for the most part the NATO protests have been peaceful.
Veterans lead peaceful, anti-NATO march to McCormick Place
The protesters had permits for Sunday's Grant Park rally and parade, which was expected to be the largest anti-NATO event during the Chicago NATO summits. As many as 2,000 people attended, officials said.
Dozens of world leaders are in town for the NATO summit, which is being held at McCormick Place on May 20 and 21. The first NATO session was called to order at 2:10 p.m., just minutes after the anti-NATO march stepped off at 2:05 p.m.
The anti-NATO march was led by dozens of U.S. military veterans, mostly Army and Navy, who have served tours in Iraq and Afghanistan. Over the week, the vets have shared their stories of disenchantment about a mission they say changed from disarming a country, liberating a country and then occupying that country. They're in town to argue on an international stage that troops should be withdrawn from Afghanistan before 2014.
"For every house that we enter, if there weren't terrorists there before, there are now," Graham Clumpner said.
"The military values the mission over the lives of these soldiers who recognize a very legitimate moral dilemma," Brock McIntosh said.
Also, they want full mental health care benefits for veterans.
At the end of the parade route, veterans threw their NATO medals over the fence that the Secret Service put up as a perimeter around McCormick Place. Each of them spoke briefly.
"We don't want your medals, we want to give them back because these are dishonor to hold, we want to give them back because we stand in solidarity with the people of Afghanistan, Iraq and all victims of occupation around the world," Scott Kimball said earlier Sunday.
"As veterans we swore to protect. We are once again going to step out front, make ourselves vulnerable and represent the majority of the people in this country. And give our medals back," Jacob George said.
The veterans had hoped a NATO representative would meet the group and take the medals back as a symbol of recognition.
The Associated Press contributed to this report.