SAN DIEGO (CNS) - Bogus bomb threats were called in to public schools in the East Village, Sherman Heights and University City Friday morning, prompting lockdowns and evacuations while police searched and cleared the three campuses.

Menacing calls were received about 9 a.m. at Sherman Elementary School on 22nd Street and Curie Elementary School on Governor Drive, according to San

Diego Unified School District officials.

Staffers at both schools notified police, and students were evacuated to a safe place on campus as officers and service dogs were summoned to comb the

grounds and buildings for hazards. The searches were complete and the security alerts lifted by 10:45 a.m., after which classes resumed, district spokeswoman Linda Zintz said.

A third bomb threat, meanwhile, was directed at San Diego Early/Middle College on the grounds of San Diego City College on Park Boulevard. The SDUSD

school and another building were evacuated.

School police conducted a security sweep of the downtown campus and lifted the lockdown shortly after noon, according to district officials.

No explosives or other types of hazards were found at any of the schools, the spokeswoman said.

It was unclear if the same person was responsible for all three threats.