Five to 10 people were involved in a fight Friday night at Los Osos High School following a game against their rival, Rancho Cucamonga High School.
Deputies say security guards broke up the fight and detained two people. That's when about 300 people gathered around them to see what was going on.
Deputies called for assistance from other law-enforcement agencies and shot pepper spray into the air.
The crowd then dispersed. No injuries were reported.