Fremont police released all students from Irvington High School late Wednesday afternoon after the campus was locked down for hours because of a suspicious person reported with a handgun.

"At this time we have not located that individual," Fremont police said in an email statement. Police said they would remain on scene to conduct a final security sweep of the campus.

The school was put on lockdown following a report of a suspicious, possibly armed man at the campus at 41800 Blacow Road, police said shortly after 1 p.m.

Parents were initially directed to go to a local Walgreens store, but were later being told to go to the Fremont Unified School District Office at 4210 Technology Drive, police said. School buses transported students to that location.

NBC Bay Area's helicopter captured images of students being frisked by police as they evacuated from the school about 1:45 p.m.

Students who regularly drive, walk, take a school bus or public transportation had to remain on campus until the school is cleared, police said.

As a precaution, police also locked down Robertson High School, O.N. Hirsch Elementary School and Horner Junior High School.

Fremont police took to Twitter to dispute rumors of shots fired. "Report is one suspicious male individual seen on campus at 12:45 with a handgun," the department tweeted.

Bay City News contributed to this report.