Police in Kent, Ohio deployed tear gas and flash-bang devices to clear out large groups of students near Kent State University after fights broke out at an annual "College Fest" celebration Saturday night.
Students attending the party reported beer bottles were being thrown and that ambulances were called to the scene, the Cleveland Plain Dealer reported.
Cleveland NBC affiliate WKYC-TV reported some of the 3,000 attendees threw beer bottles at police officers and that the Kent Fire Department was dispatched after a couch was set on fire near a roadway.
There were also reports of a man with a gun at the gathering, though police didn't find anyone, according to the Kent Record-Courier.
A Kent State spokeswoman told WKYC the university was "closely monitoring" the events and "supports the city in its efforts to keep celebrations safe for everyone involved."
Most of the partygoers were cleared out by 8 p.m., the Record-Courier reported. At least four people were believed to have been taken to local hospitals as a result of injuries.
Watch additional footage of the chaos below, via student media site KentWired: (Content warning -- some strong language)