He was described as a 14-year-old of Hispanic descent.
The boy injured was also 14, and police stated that he was taken to the hospital after being shot in the arm. The suspect, also a boy, was detained off campus by officers, who recovered a rifle, according to the department.
Additional reporting from Newsy affiliate CNN.
Neither teen has been identified.
It wasn't clear Friday afternoon if the shooting happened outside or inside the school.
"All of the Palmdale Elementary Schools were put on lockdown". "We feel very confident that our schools our safe".
The Bureau of Alcohol, Tobacco, Firearms and Explosives [ATF] tweeted that they were responding to the incident.More news: Moon: Support from China, Japan Essential on Road to Peace on Peninsula
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Amid a climate of heightened scrutiny for gun violence and school safety in the wake of the February 14 massacre at Stoneman Douglas High School in Parkland, Florida, the Palmdale shooting immediately sparked a frenzy on social media and in the national news media.
"All authorities are telling us right now is that they are working on the situation", Luke said.
Santa Clarita Valley Sheriff's Office deputies were searching the grounds of Highland High School in Palmdale, Officer Nicole Nishida, spokeswoman for the Los Angeles County Sheriff's Office, told ABC News.
Highland High School is located about 65 miles from Los Angeles.
One of the brothers, 16, told Munoz he heard one gunshot, and that students were running. She was waiting to learn when her son would be released.
"I thought he was joking, and I'm like, 'Don't mess around, that's not amusing, '" said mother Ana Salazar.
The shooting was reported at Highland High School in the town of Palmdale, 40 miles north of downtown Los Angeles, CBS Los Angeles said.
Officials say there's no evidence of a shooting at an elementary school in the California city of Palmdale.