BOULDER, Colo. (AP) — Authorities have fielded hundreds of tips involving a massive weekend gathering near the University of Colorado at Boulder in which participants damaged cars, set off fireworks and tossed bottles and rocks at police, slightly injuring three officers, officials said Monday.

Boulder County health authorities, meanwhile, warned of a possible surge in coronavirus cases because of the Saturday night melee in which as many as 800 people — few wearing masks — flooded streets in a neighborhood known as University Hill, home to many university students as well as residents.

No arrests had been made, but Boulder police and other police agencies had received more than 700 tips, including photos and cellphone video of the violence, police spokeswoman Dionne Waugh said. Witnesses were encouraged to report information through a police tip line and to university authorities.

A law enforcement armored vehicle and a fire truck were damaged, as were several private vehicles.

Caroline Wiygul, a junior majoring in environmental studies and English, said she was running errands with a friend on Saturday afternoon when about 100 people milling in the street blocked their way home. They parked their car in an alley, called police and hurried to a friend’s house, where they spent the next six hours inside as the melee outside grew larger, louder and more violent.

“When we first called police they said they were handling it,” Wiygul said Monday. “But it wasn’t until 8:30 when police and SWAT came and told people to vacate the area, then used tear gas to clear the street.”

“It was really stressful,” Wygul added. “It’s upsetting because obviously, it became a big public health risk. I don’t think the police handled it that well. I think the party could have been shut down early in the afternoon.”

She and her roommates joined dozens of other students in cleaning the streets on Sunday.

Boulder Police Chief Maris Herold said a “tactical decision” was made to withdraw some officers when a group of about 100 people started to rush them. It took more than three hours to disperse the crowd, according to a timeline she provided. No arrests were made at the scene, even though three officers at a command post were injured by rocks.

University Chancellor Philip Distefano warned that any student involved in violence, property damage, refusing to disperse or violating virus-related protocols faces discipline up to expulsion.

Health officials urged anyone who was at the scene to quarantine for at least 10 days and to get tested for COVID-19. CU Boulder students returned to campus for hybrid and in-person learning in mid-February.