Authorities say a lockdown at El Camino Real High School has been lifted and several students were taken into custody.
The incident started Wednesday when two students got into an argument, and one of the students allegedly threatened to bring a gun, or made some sort of gesture that he had a weapon, say police.
The other student alerted staff, and the school went into lockdown.
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"We are on lockdown -- we have an unconfirmed report of a student with a weapon on campus. More news as we have it," read a message on the school's website posted Wednesday afternoon.
About 3:30 p.m., school officials posted on the website that "All students and staff are safe."
Students were finally released about 4 p.m. They normally leave at 3:15 p.m. The lockdown lasted about an hour.
Last Wednesday, El Camino Real High School was also in lockdown after Los Angeles school police officer Jeff Stenroos was shot while confronting a suspected thief near campus. That suspect eluded authorities. A sketch was released last week in that case.
The two incidents are not related, say authorities.
Nearby Hale Middle School was also temporarily placed on lockdown as a result of Wednesday's incident.