Updated after the jump: Two other suspects have been arrested; the teen who allegedly brought the gun to school was booked on suspicion of assault with a deadly weapon. See Wednesday's story about another shooting near an L.A. high school campus, this one injuring a police officer.

Gardena High School was on “lock-down” Tuesday after a gun discharged on-campus, sending two students to the hospital.

Reports indicated a teen who allegedly brought a gun to campus in a backpack was in custody.

Robert Alaniz, an L.A. Unified School District spokesman, told the ABC7 the backpack was accidentally dropped, causing the gun to discharge about 10:40 a.m.

” … A student took a gun to school in a backpack, and that that student had dropped

the backpack and consequently the gun discharged,” he said.

Two students were hit and one was in serious condition, the other was critical, according to ABC7.

KCAL9 reported the suspect was 15-years-old.

Parents were told to stay away for now. An info line was set up: 310-354-3400.

Added: Alaniz told KCAL9 the suspect seen on TV being taken into custody was the suspect authorities were looking for.

Update: KCAL9 reported a female shot in the head was critical and that the other victim in serious condition was a male struck in the neck.

The station reported that both injuries were the result of only one round having been fired.

Earlier reports of three people having been shot by a black-clad gunman on the loose on-campus appear to be untrue.

Update #2: A doctor says the boy was shot first, with the bullet passing through his neck and then striking the girl in the head.

She was being operated on at Harbor-UCLA Medical Center.

LAPD Deputy Chief Patrick Gannon said both victims are 15 and that the suspect is a 17-year-old boy.

“The round from that gun hit both of the students,'' Gannon said. “The student then that was responsible for bringing the backpack into the classroom fled from that particular classroom and went to another. We have subsequently taken him into custody.''

About 3,000 students were held on campus via a “lock-down” until early afternoon, when they were allowed to leave.

Update #3: Late Tuesday L.A. Mayor Antonio Villaraigosa issued this statement:

“I am deeply saddened by the news of this incident today at Gardena High School. No student should ever fear for his or her life within the halls and classrooms of our schools. We must work together to ensure safety in and around our schools so that all students can benefit from an environment conducive to learning. My thoughts and prayers are with the families of the two victims of this tragic accident.”

Update #4: Two teens from the school were arrested Wednesday. The Los Angeles Times reports that the pair is suspected of helping the 17-year-old who allegedly brought the gun on campus hide while officers searched for him.

That boy was arrested on suspicion of assault with a deadly weapon.

First posted at 11:53 a.m. January 18.

-With reporting from City News Service. Got news? Email us. Follow us on Twitter, too: @dennisjromero.

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