MANTECA, Calif. » Authorities said six teenagers were injured after someone tossed an explosive device into a backyard party in the Northern California city of Manteca.

Police officials said about 60 high-school aged teens were at the party Friday night when someone threw explosive device, possibly a modified firework, over a fence and into the backyard.

The explosion injured six juveniles, and five of them remain hospitalized Saturday.

A police statement said two of the victims suffered serious injuries and one was airlifted to a hospital in the San Francisco Bay area to be treated for an eye injury.

Investigators are seeking the public’s help to identify the suspect.