Update at 3:38 p.m. ET: KTLA reports that all the students involved are 10th graders and that the two victims are 15 years old. The girl suffered the head wound and the boy was grazed by a single bullet.

Update at 3:17 p.m. ET: Los Angeles police now say only two students, a boy and a girl, were wounded in the shooting, which they say was accidental.

The student taken into custody had a gun in his backpack and it discharged when he slammed it down on his desk, police say. School officials say one student suffered a serious head wound and the other a superficial graze wound from a single bullet.

KTLA-TV reports that Gardena High School does not have walk-through metal detectors but uses hand-held detectors instead.

A news conference is expected in the next 10 to 15 minutes.

Update at 2:50 p.m. ET: Police have arrested a young man dressed in black who is suspected of shooting three students at Gardena High School in Los Angeles county, KTLA reports.

KTLA's live broadcast showed police, who were just outside a classroom door, subduing the suspect, who emerged after several apparent hostages left the room. KTLA says the shooter has now been arrested.

Update at 2:45 pm. ET: KTLA reports that police have made contact with a gunman inside Gardena high school where three students have reportedly been shot.

The Associated Press quotes Gardena police Lt. Steve Prendergast as saying the shooter is believed to be a student. Prendergast says the three victims have been treated by paramedics and transported to a hospital.

The lieutenant says police were alerted by a teacher who called police at 1:41 p.m. ET.

Earlier report: At least three students have been shot at Gardena high school in Los Angeles county and the school is on lockdown, KTLA reports.

At least one of the injured has been taken to a hospital, but the condition of the victims remain unclear.

KTLA says the suspect is 18 years old and is believed to be a student. KTLA says police have identified the shooter, but have not released the name.

Update at 2:25 p.m. ET: KTLA reports that two students, a girl and a boy, were wounded in the shooting. The victims were taken from the school by ambulance, KTLA says.

The condition of the victims remains unclear.

CNN reports that police have identified the suspect, but have not released the person's name. The person is described as dressed in black.

Earlier posting: CNN reports that three people have been shot at California's Gardena high school. It says the school is currently on lockdown.

Gardena, with a population of around 57,000, is located in Los Angeles county.

Update at 2:21 a.m. ET: The Los Angeles Times reports that as of 2:13 p.m. ET the gunman was still at large.