At least two people - possibly teachers - were shot and injured at a high school in San Diego today, less than three weeks after two students were killed in a gun rampage at another area high school, US officials said.
A fire department spokesman said there were reports of a third person being shot.
Local television reported today the injured were two teachers and that one suspect had been arrested at Granite Hills High School in a suburb east of San Diego.
Another suspect was thought to be at large and, possibly armed with a shotgun.
Residents were asked to stay out of the area while police searched for the second suspect.
A witness said he heard six or seven shots and then saw students running out of the school via a back entrance, calling on their cell phones for help.
Students at the school, which has 2,900 pupils, were taken to a nearby elementary school where their parents were called to pick them up.
El Cajon is adjacent to Santee in California where two students were killed and 13 others injured when a student opened fire with his father's gun at Santana High School on March 5.
That was the worst act of violence in a US school since April 1999 attack on Columbine High School in Colorado in which 15 people were killed, including two teenage gunmen who took their own lives.
Students at Granite Hills High School described a frightening scenario which seemed almost a repeat of what happened in Santee.
One boy told CNN he heard about seven shots fired: "I was walking from the bathroom and I heard the shots rang out and it sounded like an explosion from a chemistry classroom. ... Then a couple more. When I heard the other ones go off I just ran to the car."