A 16-year-old student opened fire at a public high school in Southern California Thursday morning, killing two of his classmates and injuring three others, authorities said.

The suspected gunman, who launched the deadly assault at Saugus High School on his birthday, was taken into custody and is currently in “grave condition” at a local hospital from a self-inflicted gunshot wound, according to authorities.

Police and firefighters responded around 7:40 a.m. Thursday to reports of a shooting at the school in Santa Clarita, about 40 miles north of Los Angeles.

Video footage from the scene shows “the subject in the quad withdraw a handgun from his backpack, shoot and wound five people, and then shoot himself in the head,” authorities said.

L.A. County Sheriff’s Department Capt. Kent Wegener said the suspect used a .45 caliber semi-automatic pistol, which was recovered at the scene with no more rounds in it. Wegener said the officers who first arrived at the scene found six students with gunshot wounds in the school’s quad and transported them to local hospitals, later realizing one of them was the gunman.

Authorities said Thursday a 16-year-old female student and a 14-year-old male student died after the incident. The surviving victims include a 14-year-old girl and a 15-year-old girl.

L.A. County Sheriff Alex Villanueva said the suspect—described as a 16-year-old boy wearing a black hat and black clothing—is a Saugus High School student and was one of the first students evacuated to a local hospital.

“Among those that were transported turned out to be the suspect who is currently in the hospital in grave condition,” Villanueva said. The suspect’s girlfriend and his mother are currently speaking with authorities.

Megan Puettmann, a 17-year-old senior, told The Daily Beast she was in class Thursday when she heard “very faint gunshots.”

“It was confirmed when someone rushed into my class screaming of a shooter,” said Puettmann, calling the experience “traumatic.”

The teenager said she and her classmates hid in the back corner of the classroom until they were evacuated by police an hour and a half later—which “felt like a lifetime.” “There was nowhere to hide,” she said, noting the classroom only had one door.

“This should never have to happen to anyone ever,” she said. “I just want to take this experience and speak up against gun violence and mental health awareness so that this won’t ever happen again. Having to worry about my friend’s lives and worry about ever seeing my family again is a feeling you won’t ever understand unless you are there.”

Aerial footage obtained by NBC News showed the initial chaos of the shooting scene, with a line of students evacuating from the school with their hands raised in the air.

“I hate to have Saugus added to the names of Columbine, Parkland, and Sandy Hook, but it's a reality that affects us all throughout the nation,” Villanueva said.

According to The Los Angeles Times, several students were placed on gurneys and transported to ambulances in the school’s parking lot. At least one individual was found injured in the school’s choir room, authorities said.

One high school junior, who identified herself as Riley, told KTLA she was outside the library with her friends before school began when she heard the sound of gunshots.

“We heard one, two gunshots. We looked at each other, it took so long for us to process. Then we heard three or four more gunshots,” Riley said, adding that she fled before she realized what was happening. “I heard a bullet hit the wall right next to where we were standing... we ran as fast as we could. There were hundreds of us just running as far away as possible,” she said.

Another student, Sharon Orelana Cordova, told NBC San Diego she hid under a table in a nurse's office during the incident until officers arrived.

“When I got out, I saw this person lying on the ground with blood all over,” she said.

Several family members met evacuated students at a local park, where according to one grandmother a student learned her friend was fatally shot.

“I was told she’s at the park. That her friend had been killed. And that she’s very sad. That she’s crying,” she emotionally recounted to NBC Bay Area in Spanish, adding that her granddaughter was safe.

Former California Rep. Katie Hill, a Saugus High School alum who still lives in the community, called the shooting “your worst nightmare.”

“Every single member of Congress is constantly in the back of their head as to whether something like that is going to happen in your home district because it’s the worst thing that can happen,” said Hill, who resigned less than two weeks ago.

California Gov. Gavin Newsom also issued a statement Thursday stating he is “closely monitoring” the incident and working with law enforcement.

“I am closely monitoring the incident at Saugus High School in Santa Clarita this morning, and my Administration is working in close coordination with local law enforcement,” Newson said. “Jennifer and I extend our thoughts to the parents, families and friends of the students and faculty, and the Santa Clarita community.”

Editor’s Note: The sheriff’s office at one point said three students had died in the shooting, but later amended the death toll.