SAN LORENZO (CBS SF) — Authorities in the East Bay said they arrested a male teen student at San Lorenzo High School Tuesday afternoon in possession of a loaded 9mm handgun, according to the Alameda County Sheriff’s office.

According to authorities, at 12:45 p.m. on Tuesday, the 16-year-old male was initially detained and then arrested after being found in possession of the loaded weapon.

School officials said that the campus was placed on lockdown after officials received the report of a weapon on school grounds. According to an email that was sent to all San Lorenzo High students and families, the school “followed all protocols, contacted law enforcement, and initiated our lockdown process and procedures.”

The lockdown was eventually lifted after the armed teen was found and the firearm secured. Students were safely dismissed to their next class, school officials said.

No one was injured in the incident.

The Alameda County Sheriff Twitter account posted an image of the weapon that was seized.

12:45pm, a 16 year old male student was detained/arrested in class at San Lorenzo HS with this loaded 9mm handgun. Students, staff and school resource officers worked together to bring this to a safe conclusion. #SchoolSafety #NotHappeningAtOurSchool pic.twitter.com/9MzcjcadnB — Alameda County Sheriff (@ACSOSheriffs) May 29, 2018

Authorities did not offer any additional details on the arrest or where the teen suspect obtained the firearm.