DENVER » An apartment complex near Colorado State University that used Facebook to advertise "the biggest pool party of the year’" got more than it bargained for — at least 2,000 people, most of them college students, showed up.

It wasn’t long before the police followed.

Four people, including two CSU football players, were arrested at the Fort Collins apartment complex on Saturday. Ten people were taken to the hospital, most of them for overconsumption of alcohol or minor injuries.

"Some people came from as far away as Denver for this back-to-school party," Fort Collins police Lt. Hal Dean said on Monday.

The party’s Facebook page had nearly 3,000 registered people. Dean said police estimated at least 2,000 people showed up at the complex about 65 miles north of Denver. Officers had to shut down surrounding streets while they cleared the complex.

The use of social networks such as Twitter and Facebook to spread word of everything from parties to freedom movements has increased exponentially in recent months. In some cases, the events have led to street trouble.

In Los Angeles in July, a simple tweet by DJ Kaskade telling his followers about a free block party lured thousands of raucous ravers to the landmark Grauman’s Chinese Theatre.

Things turned rowdy, with revelers hurling bottles at police and some jumping on a squad car.

In Fort Collins, firefighters and ambulance crews told police of the out-of-control party at the Ram’s Pointe apartment complex.

Dean said police weren’t monitoring the Facebook party site — something some police agencies have begun to do after social media was used by rioters in England to organize looting and by organizers of so-called flash mobs in several U.S. cities.

The apartment complex did not respond to telephone calls seeking comment on Monday.

Police said complex management could be cited under the city’s nuisance gathering ordinance.

Police said Monday that James Skelton, 21, was cited for third degree assault. The charges were related to a fight. Zachary Tiedgen, 21, was cited for disorderly conduct. Two others were charged.

Skelton is a linebacker and Tiedgen a defensive end on the CSU Rams football team, assistant athletic director Gary Ozello said. Head coach Steve Fairchild refused comment and said the incident is under investigation.

Ozello said the athletic department has a strict social media policy that warns players not to post anything to embarrass the team.