SUMMIT COUNTY, Colo. (KDVR) — All Summit County schools were placed on lockdown after a threat was called in.

According to the Summit County Sheriff’s Office, deputies were called to Summit High School on reports of an “active assailant” outside the high school.

Out of an abundance of caution, the entire district was put on lockdown. At 11:30 a.m. all schools were moved to a secure status except for Summit High School, which remained on lockdown while police investigated.

The Summit School District serves more than 3,450 students who live in Breckenridge, Dillon, Frisco and Silverthorne.

The Sheriff’s Office said all students and staff were safe and no threat had been identified at the schools.

Photos were circulating of a man with a gun outside the school. The Sheriff’s Office confirmed the person was a law enforcement officer.