VAN NUYS, Calif. (CNS) — A fight on the campus of Van Nuys High School sent three students to hospitals Wednesday, two of them with stab wounds, and three other students were detained for questioning.

The melee was reported about 10:55 a.m. at the school in the 6500 block of Cedros Avenue, according to the Los Angeles Police Department.

Los Angeles Unified School District Superintendent Alberto Carvalho said a total of three students were taken to hospitals — two of them with stab wounds and another as a result of "battery actions."

According to the Los Angeles Fire Department, the patients were all teenage boys, with one in serious condition, one in moderate condition and the third in fair condition. A fourth student was evaluated at the scene but was not taken to a hospital.

Carvalho said nearly a dozen students may have been involved in the unrest.

It was unclear what precipitated the fight in the campus quad, but Carvalho said three students had been detained for questioning. The school was placed on lockdown immediately after the fight. Carvalho said students were back in their classrooms by early afternoon, and their lunches were being brought to them, rather than having students congregate in the cafeteria.

He said the school would operate normally for the rest of the day with a normal dismissal, although students might be released on a staggered basis to prevent crowds from gathering.

Carvalho noted that under a policy approved by the LAUSD Board of Education roughly two years ago, no police officers are located on the district's school campuses during the day. But he said police responded to the Van Nuys High School campus within three minutes of the fight being reported, a response he called "very appropriate."

He said that despite the board policy against on-campus officers, there will be a police presence on the Van Nuys campus in response to the fight. It was unclear how long that presence will continue.

"Once you know better, you must do better," Carvalho said. "Since I arrived in Los Angeles, I have directed regional superintendents and the principals, if they know of, suspect of any information that would put them in the position of feeling that the presence of a police officer ... to ensure safety and security of the school would be appropriate, they can request the presence of (police). As of today, Van Nuys will have the presence of an officer within its school facilities."

He urged anyone who might suspect there is a potential threat to campus safety to come forward.

"This is the type of incident that is difficult to anticipate, and we have to rely on what people know and can convey to us," Carvalho said. "These don't necessarily happen spontaneously. So we continue to urge parents or students to tell us about what they know so we can prevent these types of incidents from occurring."

According to Carvalho, there are 2,200 students at Van Nuys High School. The campus also houses a continuation school with another 200 students.

He said counselors were brought to the campus to provide support to students and staff, and counseling will also be offered to the families of students who were involved in the fight.