Kathryn Kirsch/iStockBy KARMA ALLEN, ABC News

(CHICAGO) -- At least 100 people were arrested in Chicago overnight as looting and violence overtook the streets, injuring multiple police officers, authorities said.

Thirteen officers were injured, including a sergeant who was attacked with a bottle, and at least two civilians were shot during the unrest after midnight Sunday, in the early hours of Monday morning, as hundreds overran the city's upscale Magnificent Mile shopping district and surrounding areas with vandalism and violence, authorities said.

The suspects face several charges, including looting, battery against police and disorderly conduct, authorities said. Investigators are also searching for suspects who fired shots at police, Chicago Police Superintendent David Brown said on Monday.

"In one incident, officers were arresting a suspect who was seen carrying a cash register he had looted out of a store," Brown said. "As officers were making the arrest, another vehicle passed by the officers and fired shots at the officers, as their vehicle turned the corner, resulting in an exchange in gunfire between officers and the suspects. A bullet was found lodged in the cage of the police vehicle."

The officers were not wounded by gunfire.

Chicago Mayor Lori Lightfoot said she implemented a community protection program -- a lockdown with massive police presence -- that will be in place “for foreseeable days until we know our neighborhoods are safe.”

Lightfoot said the criminal activity had nothing to do with "legitimate" organized protests and described it as "an assault on our city.”

"These individuals engaged in what only could be described as brazen and extensive criminal looting and destruction. To be clear, this had nothing to do with legitimate, protected First Amendment expression," Lightfoot said on Monday.

Investigators said the unrest was sparked Sunday afternoon by inaccurate reports online about an unarmed juvenile being shot by police in the Englewood area. The shooting victim was actually a 20-year-old man who allegedly opened fire on police while being chased, authorities said.

"Tempers flared, fueled by misinformation as the afternoon turned into evening. CPD became aware of several social media posts encouraging looting downtown," Brown said. "Officers were dispatched to our downtown area once we got word of the social media posts. Four hundred officers were dispatched to our downtown."

Much of the unrest happened along the Magnificent Mile, one of the city's most-popular tourist attractions, where looters were seen stuffing vehicles with shopping bags full of stolen merchandise and store equipment.

ATM machine were compromised, cash registers were stolen and at least one bank was broken into, according to the Chicago Tribune.

City officials said residents should expect a heavy police presence downtown until further notice. Lightfoot said the city was still "working on the specifics" of a looming lockdown that could include closing some bridges and expressways.

"We are working on the specifics now," Lightfoot told reporters Monday. "We are looking at the bridges. But we want to make sure obviously that the people who work and live downtown have easy access to the downtown area."

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