SAN MATEO (AP) -- San Mateo police Saturday cleared out a community park after a work crew found what a police spokesman called a "homemade explosive device."

Police say a park employee found three clear plastic bottles containing liquid with a strong chemical smell at Casanova Park Saturday morning.

A San Mateo County hazmat team and the bomb squad were called in to the remove the bottles. The park and a nearby residential area of about 15 homes were also evacuated. Other neighborhood residents were urged to stay in their homes.

No additional details were released, but Norris said the bottles will be sent to the county's crime lab for analysis.

Investigators believe the discovery of the materials is an isolated incident.

No arrests were made as of late Saturday, and there were no injuries.