A shooting has been reported at Highland High School, the sheriff's office told Fox News. It occurred a little after 7 a.m. local time, according to media reports.
One person has been shot in the arm and is not at the local hospital, according to the police.
Highland High School has been cleared by deputies. An active investigation is still ongoing.
READ MORE: Lay Down Your Arms: 2017 Marked Most Active Shooting Incidents Yet Says FBI
A suspected gunman has been detained after the reported shooting early in the morning at the high school in Palmdale, California, CNN reported.
The Los Angeles County Sheriff's office said earlier that multiple deputies were responding to a possible shooting at Highland High School.
Police have also investigated reports of shots heard at the nearby Manzanita Elementary School, but the sheriff's department said in a subsequent Twitter post that the school was clear of any shooters.
Twitter and Facebook users have been posting tweets, warning about the incident.
On February 14, Nikolas Cruz, a student who had been expelled for "disciplinary reasons," is alleged to have entered his school in Parkland, Florida, with an AR-15 rifle and opened fire, killing 17 people and injuring 14 more.