SANTA CLARITA, Calif. -- A male student opened fire on classmates Thursday morning at a Southern California high school, killing a 16-year-old girl and a 14-year-old boy, Los Angeles County Sheriff Alex Villanueva told reporters.
Three other students were wounded and hospitalized, he said.
The suspected shooter, who turned 16 on Thursday, was hospitalized with a gunshot wound. Officials said he is in grave condition.
The shooting at Saugus High School in Santa Clarita began before classes started, officials said, sending some students streaming out of the building as others hid.
Video obtained at the scene clearly shows the suspect taking a .45-caliber pistol from a backpack before shooting five people and then himself, Capt. Kent Wegener of the Los Angeles County Sheriff's Department told reporters.
Authorities are working to obtain any other video from campus and cell phone video from students.
Emergency workers took several people out of the school on gurneys, and large groups of people walked out single-file with armed escorts, aerial footage from CNN affiliates shows.
Officials shepherded students to nearby Central Park, where parents were told to meet them.
The shooting happened about 20 minutes before the start of school, according to Hannah de Caussin, whose daughter attends Saugus.
Some students fled, and others hid
Some students fled the building immediately, and others took cover inside rooms, another student told CNN affiliate KTLA.
"It was one and then four quick ones, so bang, and then bang, bang, bang, bang," the girl said after leaving the building.
Students are trained to take cover in classrooms, but she and some others ran out because they thought the shooter was near where they would have hidden, she said.
"We ran through the fence, luckily it was open, and we got as far away from campus as we could," she said.
"We were texting all our friends and making sure they were safe. They said they were hiding and they were scared. It scared us because they're our friends and we didn't want anything bad to happen to them."
Another student, Brooklyn Moreno, told CNN affiliate KCBS that she was waiting for a bell to ring to signal her first class when she heard the first shot.
"Everyone thought it was a balloon, and it got really quiet. And then two more shots, and then everyone just ran out of the school," said Brooklyn, who added that she ran across a street to someone's house until someone came to pick her up.
Grandfather: Students ran down my street screaming
Larry Everhart, a grandfather of a Saugus High student, told KCBS that he was leaving his house to get coffee when he saw students running down his street screaming.
"They were saying, 'Can I come in your house?' It was about 20 of them. I wanted to make sure they were safe, so I got them in there," he said.
School officials are sending students to Central Park, where parents should meet them, the district said.
Everhart's neighbor, a police officer, eventually told him he could go to the park, where he found his granddaughter safe.
"My granddaughter threw her arms around me and was hugging me, and I was just so happy she was still alive," he said.
Rumors of online threats are being investigated
Investigators will check rumors that the suspect may have posted threats on social media, county Undersheriff Tim Murakami said on Twitter.
"If you ever learn of posted threats please notify us ASAP," Murakami wrote.
All schools in Santa Clarita's William S. Hart school district were temporarily locked down as a precaution, but the restrictions were later lifted, the district said.
Saugus High School, about 30 miles northwest of Los Angeles, has about 2,400 students, according to the district.