Police officers stand guard outside Salvador Castro Middle School in Los Angeles, the United States, Feb. 1, 2018. Five people were injured, including two students shot, in a classroom shooting Thursday at the Salvador Castro Middle School in the western U.S. city of Los Angeles, local authorities said. (Xinhua/Zhao Hanrong)

LOS ANGELES, Feb. 1 (Xinhua) -- Five people were injured, including two students, in a classroom shooting Thursday at the Salvador Castro Middle School here, local authorities said.

A 15-year-old boy who was shot in the head was in critical condition and a 15-year-old girl who was shot in the wrist was in stable condition, according to Los Angeles Police Department (LAPD).

"We had some type of a shooting occurrence inside a classroom," said Los Angeles (L.A.) School Police Chief Steve Zipperman during a press briefing at the scene.

Police arrested a girl believed to be 12 years old, who is suspected of opening fire in the classroom, and recovered a gun after the shooting, Zipperman said. Referred to as a "person of interest," the girl was seen being handcuffed and taken into police custody.

The shooting was reported to police at around 9 a.m. local time (1700 GMT). Police rushed to the scene and conducted room searches at the campus.

Three other people, including two children and a 30-year-old woman, suffered minor injuries that were not caused directly by the shooting.

Police officials told reporters that they don't know the exact number of students on the scene when the shooting happened. It is still too early to determine the motive of the suspect.

There was a heavy police presence at the location. The campus was on lockdown following the incident. A lot of anxious parents and relatives were waiting outside the campus.

"We heard the shooting. It's very loud," said a seventh grader who named herself Melanie. "The teacher told us that kids got injured, and we will be OK."

The girl told reporters outside the campus that she was scared because "it could have been in our classroom."

Melanie said the school did security search sometimes, but didn't do it Thursday morning.

"I feel better and relieved after seeing my son," said Randy Hernandez, a father who had rushed to the scene waiting outside the campus.

Salvador Castro Middle School has a total enrollment of 428 students and 22 full-time teachers. More than 92 percent of the students are Hispanic, according to the data on the website the www.localschooldirectory.com.

L.A. Mayor Eric Garcetti told ABC7 at the scene that it was unclear if the shooting was intentional or accidental.

"We need to find out how did that gun get into the school," Garcetti said.

To date, a total of 14 shootings have occurred on school campuses across the United States, according to Everytown for Gun Safety, a non-profit organization committed to measuring America's gun violence with comprehensive and up-to-date data.