Fans of the University of Arizona took to the streets of Tucson Saturday night, and police responded in riot gear. After their team lost in the NCAA tournament, crowds poured out of bars and restaurants near the university.
The gathering was peaceful at first, but then fans started throwing objects at the police, like cans, bottles and fireworks.
Tucson police declared it an unlawful assembly and responded with pepper canisters to break up the large crowd.
Officials say no tear gas or rubber bullets were used.
15 people were arrested on misdemeanors. Three of them had minor injuries.