A bomb threat called into San Clemente High School on Wednesday afternoon led the Capistrano Unified School District to place 13 of its schools in the district on lockdown, a sheriff’s official said.

Students at San Clemente High were told to stay indoors after someone called the school around 1:30 p.m., claiming a pipe bomb had been placed on the campus, according to Orange County Sheriff’s Department Lt. Jeff Hallock.

The sheriff’s department had no reason to believe the threat was credible, but it was being taken seriously, officials said.

San Clemente High principal Michael Halt said he was in a classroom when he received notification about the call. He said everyone reacted calmly.

“We certainly are comforted by the fact that our staff and students know how to react to this kind of situation,” Halt said.

Halt has been head of the school for about 18 months. In that time, he’s been through three drills and two actual emergency events.

By 4 p.m., the sheriff’s bomb squad – using explosives-sniffing dogs – had cleared the San Clemente campus, Hallock said.

The majority of schools in Capistrano Unified School District were placed on lockdown after the threats were made, a district official said.

Students at the following schools were told to stay indoors during the threat: RH Dana Elementary, Concordia Elementary, Palisades Elementary, Las Palmas Middle, Vista Del Mar Middle, Del Obispo Elementary, San Juan Elementary, Ambuehl Elementary, Kinoshita Elementary, Lobo Elementary, San Clemente High, Dana Hills High and San Juan Hills High.

The school district sent a safety alert asking parents not to come to campus “to ensure that the sheriff’s department can perform necessary tasks to keep students safe.”

The sheriff’s department bomb squad focused its search on the San Clemente High campus, using dogs to comb the area for hazardous devices.

A precautionary sweep of the other campuses was conducted by school officials, and students were released as the schools were deemed safe.

By 3 p.m., Dana Hills High School had been cleared of any dangers, and students were dismissed.

By 3:30 p.m., all schools except San Juan Hills High and San Clemente High had been cleared for release. Students who normally took the bus home from school were to be transported by bus to their designated stops.

Officials at Ambuehl Elementary said that students in Ms. Tatarian and Ms. Sullivan’s classes who are returning from their field trip will be taken to Saddleback Church in Rancho Capistrano, 29251 Camino Capistrano, San Juan Capistrano. Parents should arrange pickup of students there.

“We sincerely thank you for your patience and understanding as we worked through this situation to ensure the safety of our staff, students and community,” school district officials said.

Staff writer Louis Casiano Jr. contributed to this report.