A Southern California high school was evacuated on Wednesday after a note was found in the belongings of a U.S. Navy corpsman claiming he had placed explosives there, authorities said.

Police were searching for the corpsman, identified as 22-year-old Daniel Morgan, saying he had gone AWOL earlier in the day from the nearby Camp Pendleton Marine base, Orange County Sheriff's spokesman Jim Amormino said.

Some 3,200 students were pulled out of classes at San Clemente High School at around 9 a.m. after military police notified sheriff's deputies about the note, Amormino said.

Some 180 teachers and other staff were also evacuated from the school, in the coastal city of San Clemente about 65 miles south of Los Angeles.

Wednesday was the first day of classes for San Clemente High School.

Amormino said the note was found in Morgan's belongings after he went missing from Camp Pendleton, Amormino said.

In his barracks they found a note that he placed explosives at San Clemente High School, Amormino told local KABC-TV. The high school has been evacuated, 3,200 students, 180 staff have been evacuated.

Police said Morgan may be driving a white Jeep Wrangler with a black top.

Amormino said the school had been locked down and a bomb-squad was conducting a room-by-room search.

Television images showed hundreds of students filing out of classes and onto a football field.

The students, who had initially been evacuated to a football field, were later moved into a gymnasium to get them out of the sun as temperatures approached 90 degrees in San Clemente.

Capistrano Unified School District officials asked that parents and community members stay away from the campus and said students would be sent home for the day.