SAN LORENZO (CBS SF) — Deputies who responded to Arroyo High School in San Lorenzo Friday afternoon following a report of a possible student with a gun arrested one student and detained two others, according to authorities.

Deputies with the Alameda County Sheriff’s Department were called to the school Friday afternoon. The department Twitter account posted that the school was locked down and deputies had found the armed student shortly before 3:15 p.m., declaring the situation safe.

READ MORE: Northbound San Tomas Expressway in Santa Clara Closed by 'Major Injury' Accident

Sgt. Ray Kelly said no shots were fired and no one was injured.

Kelly said the two students who were detained allegedly were spreading rumors that a 15-year-old male student had brought a gun to the campus.

Kelly said school administrators who heard the rumors contacted the sheriff’s office and the office sent deputies to the school. The deputies identified the student who allegedly had a gun and arrested him while he was in a class, according to Kelly.

READ MORE: SF Restaurant Apologizes for Denying Service to Armed, On-Duty Police Officers

The spokesman said that the student allegedly tried to conceal a loaded handgun he had but it was near him and the deputies were able to recover it safely.

The two students who were detained allegedly are friends of the student who was arrested with the gun, Kelly said. Chopper 5 cameras captured two people, a male and a female, being escorted to a sheriff’s vehicle.

A student at the school tweeted a photo of the inside of her classroom during the lockdown, noting how scared she was.

Shortly before 4 p.m., authorities announced that the lockdown was lifted.

MORE NEWS: Santa Clara Police Search for Elderly Man and Dog Who Went Missing Sunday

So far, authorities have not offered any details as to why the student had the gun on campus or where the student obtained the firearm.