Four people were arrested and at least 10 people hospitalized after a weekend party near Colorado State University that was advertised on Facebook grew to thousands of people.

The back-to-school party at a Fort Collins apartment complex began at 1 p.m. Saturday. Its Facebook page registered nearly 3,000 attendees.

Fort Collins Police Lt. Dave Haywood says officers were dispatched at about 3 p.m. after fire and ambulance responders were "overwhelmed with alcohol-overdose cases."

Police say two people were cited with assault, one was cited with disorderly conduct, and a fourth person was cited with interference with a peace officer. Haywood says the assault charges were related to a fight, though he doesn't think anyone was "seriously hurt."

He says he doesn't have details on the people who were taken to hospitals, but he says some of the cases involved intoxication.