(CNN) PALMDALE, California - One person was shot in the arm in Friday morning's shooting at Highland High School in Palmdale, the Los Angeles County Sheriff's Department said on Twitter.
The injured person is in stable condition at a hospital, the message said.
The detained suspect, the tweet said, is a male juvenile, and officers have confiscated a firearm
A suspect is in custody after authorities responded to reports of shots fired and a man with a gun at a Southern California high school Friday morning, a Los Angeles County fire official said.
Authorities were called to Highland High School in Palmdale at about 7:05 a.m. PT, according to Los Angeles County Sheriff's deputy Charles Moore.
Details about whether anyone was injured weren't immediately available. Witnesses who were outside the school described hearing gunshots and seeing students running from the building.
The suspect, a male, was apprehended near a Vons grocery store in Palmdale, the Los Angeles County fire official said.
School District Superintendent Raul Maldonado confirmed in a statement that there had been an active shooter on campus.
Ricky Munoz, 23, says he dropped his two younger brothers and a friend off at the high school around that time.
"About a minute later, I get a call from them saying there were gunshots" and they asked to be picked up, Munoz said.
One of the brothers, 16, told Munoz he heard one gunshot, and that students were running.
Students barricaded themselves in classroom, mom says
Nadine Luke told CNN her 18-year-old daughter called her, screaming, after she heard shots in the school. The teen was in her Reserve Officers' Training Corps class, and said students were putting sofas and desks in front of the classroom door and windows to barricade themselves inside, Luke said.
"All authorities are telling us right now is that they are working on the situation," Luke said. "The only thing I want right now is to have my daughter right here."
Lydia Gilbert, a junior at Highland, said her mother was dropping her off when a student ran up and warned her there was a shooting.
Lydia said she then heard two gunshots before she and her mom drove away.
"I was supposed to be going to school earlier than I was, but was late," she said. A shooting at the school, she said, has "actually been one of my biggest fears."
Highland High student Katharina Smith, 16, said she was driving to the school when she saw "a ton of police racing toward school."
"There were some kids running from the school, and security and sheriff were telling people to go home," she said.
A student's mother, Ana Salazar, told KCAL and KCBS that her son texted her to say a shooting had happened.
"I thought he was joking, and I'm like, 'Don't mess around, that's not funny,'" Salazar said. "And he's like, 'No mom, for reals, I locked myself up. I heard it at the other side of the school. There was one shot. And I'm locked up in one of the buildings now.'"
'Please stay clear of campus'
The school's principal posted a message on Twitter, urging people to stay away from the campus.
"Law enforcement is working to assess the situation," the message from Principal Chris Grado says. "Please stay clear of campus. Will update as soon as have more information."
Law enforcement is working to assess the situation. Please stay clear of campus. Will update as soon as have more information.— HHS Principal (@HHSPrincipalCG) May 11, 2018
At least three nearby schools -- David G. Millen Intermediate, Cottonwood Elementary and Ocotillo Elementary -- were on lockdown, employees there said.
The Bureau of Alcohol, Tobacco, Firearms and Explosives said it was responding to a shooting at Highland High School, according to its official Twitter account.
Palmdale, a city of about 150,000 people, is in Los Angeles County, about 40 miles north of downtown Los Angeles.
This is a developing story.