SAN DIEGO (CNS) - Anonymous threats of violence prompted precautionary lockdowns and searches at Clairemont and Lincoln high schools Monday. 

A male caller telephoned each of the campuses about 11:30 a.m. and made menacing statements, according to San Diego Unified School District officials.

It was unclear if the same person was responsible for both threats. Teachers kept students secured in their classrooms while campus and city police searched the grounds and buildings, SDUSD spokeswoman Linda Zintz said. Nothing hazardous had been found as of early afternoon. Zintz said she was unaware of the exact nature of the threats.