Updated at noon ET

Authorities in Los Angeles County say several people were injured when a gunman opened fire Thursday at Saugus High School in Santa Clarita, Calif. A lockdown order is now in place for the entire William S. Hart Union School District.

The Santa Clarita Valley Sheriff’s Station says “approximately 5 victims” were being treated for injuries, though it’s not yet clear whether those injuries were from gunfire or whether anyone was shot. All of the victims have been transported to hospital.

The shooting was reported around 7:05 a.m. local time, the sheriff’s department says. After deputies reached the school, they cleared out the campus and began a systematic search for the suspect on school grounds and in the nearby area.

Law enforcement officials were still looking for the gunman, whom they described as a male wearing black clothing. Nearby residents were asked to “shelter in place and report any suspicious activity,” says Tim Murakami, undersheriff of the Los Angeles Sheriffs Department.

“Deputies responded to reports of shots fired,” the Santa Clarita Valley Sheriff’s Station says via Twitter. It adds, “This is an active shooter situation.”

In an update, the department says, “If you live in neighborhoods anywhere near Saugus High, PLEASE LOCK DOORS and stay inside. If you see suspect, male dark clothing, in backyards, etc. CALL 911.”

This is a developing story. Some facts reported by the media may later turn out to be wrong. We will focus on reports from police officials and other authorities, credible news outlets and reporters who are at the scene. We will update as the situation develops.

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