SAN MARCOS, Calif. — San Marcos High School (SMHS) was put on lockdown Friday morning following a bomb threat, authorities confirmed.

Deputies, along with K-9 units from Cal State San Marcos and ATF are searching the school, according to the San Diego County Sherriff’s Department.

The call was reported to come in around 8 a.m.

In a message sent to parents and staff, the San Marcos Unified School District (SMUSD) said they received a phone call threat earlier this morning, prompting them to immediately place the campus on lockdown.

SMUSD stated, “Our law enforcement partners are on scene and conducting a thorough sweep of the campus to ensure the safety of students and staff.”

“I was behind my coworker getting ready to turn into the parking lot when all of a sudden, sheriffs SUVs are coming from both east and west,” a teacher at the high school told FOX 5.

The lockdown has since been lifted.

At 11 a.m., the San Diego County Sherriff’s Department released an update stating that parents and guardians of students were allowed to start picking up children from the campus.

Deputies will be conducting extra patrols of the school throughout the day Friday.

SMUSD released a follow-up statement at 11:11 a.m., noting the the sweep of the high school campus was completed and no threats were discovered.

Classes at SMHS were canceled for the remainder of the day based on the number of students who were unable to arrive Friday morning. 

No other schools were named in the threat, authorities said.

Earlier this week, a threat against San Marcos Elementary School was deemed not credible.

This is a developing story. Please check back for updates.