ESCONDIDO, Calif. (AP) _ Fifteen students were burned when an explosion during a high school football game sent flaming pieces of glass ripping through the bleachers.

The smoky blast detonated near the front of the stands at San Pasqual High School during the school's homecoming game against Carlsbad High on Friday evening.

The type of explosive device _ whether it was fireworks or a bomb _ was not immediately known. One witness told police it sounded like a medium-sized firework.

Sgt. Robert Healey said police had no suspects Saturday.

Some students suffered scorching on their clothing similar to cigarette burns.

None of the 15 students required hospitalization. Medics treated the wounded at the scene, and the game continued.

San Pasqual won 21-13.