Approximately 150 protestors gathered at Sheridan Road and Clark Street as part of a series of organized protests, according to the City of Evanston.
Police said an unruly crowd began throwing bricks and fireworks at officers.
One Northwestern student was arrested, according to a university spokesman.
"Late Saturday night, protesters that started a demonstration on the Northwestern campus marched into downtown Evanston. According to the Evanston Police Department (EPD), some protesters threw bricks at police officers, shined high-powered lasers into their eyes, and threw lit fireworks and smoke bombs at the officers. In response, the officers deployed pepper spray and arrested one Northwestern student, according to EPD. The student was released from EPD custody early this morning. We are awaiting additional information. The Northwestern University Police Department was not involved in the incident once it moved beyond the University's jurisdiction," according to a Northwestern University statement Sunday morning.
There were broken windows and other property damage in the city's downtown shortly before midnight Saturday.
Some of the local Whole Foods windows were boarded up Sunday morning following the overnight incident, according to police.
Several officers were treated for minor injuries, according to officials.
Other police departments from neighboring communities were also called in to help restore order.
"As we have stated before, Northwestern strongly supports the free expression of ideas and vigorous debate, abiding principles that are fundamental to our University. Northwestern protects the right to protest, but we do not condone breaking the law. Should members of the Northwestern community be found in violation of University policies, state or federal laws, they will be held accountable through our processes," the University said in a statement.
Evanston police have not said what the students were rallying over as of early Sunday afternoon.
The City of Evanston responded to the Sunday night incident, saying in part:
"When it was clear the event had transitioned from a peaceful protest to that of intentional destruction, officers deployed pepper spray to prevent injury to bystanders and police officers. Contrary to misinformation being circulated on social media, no tear gas was used. Smoke seen in any photos is from fireworks used by the protesters, not tear gas... The City of Evanston and the Evanston Police Department support and respect the rights of all individuals to protest peacefully and safely in Evanston. However, those harming the health and safety of officers and the public, damaging property, or otherwise violating the law will be arrested."
Recently, a student group has been demanding that Northwestern University cut ties with campus police.
In October, protests to abolish university police took to the streets near campus in the north suburban community.
RELATED: Evanston protestors demand Northwestern University abolish police department
University President Morton Schapiro wrote a letter to the community after an earlier incident acknowledging the concerns of injustice, but he also made it clear the school has no intention of dissolving its police department.
"We, as a University, recognize the many injustices faced by Black and other marginalized groups. We also acknowledge that the policing and criminal justice system in our country is too often stacked against those same communities. Your concerns are valid and necessary, and we encourage and, in fact, rely on your active engagement with us to make your school and our society equitable and safe for everyone. That said, while the University has every intention to continue improving NUPD, we have absolutely no intention to abolish it," Schapiro wrote.
In a letter last week, Schapiro highlighted a new safety oversight board that will be made up of faculty, staff and students.