LOS ANGELES, May 11 (Xinhua) -- A 14-year-old boy who shot and wounded a student at a southern California high school Friday morning has been arrested, according to the Los Angeles County Sheriff's Department.

The shooting happened on the campus of Highland High School in Palmdale at around 7 a.m. local time (1400 GMT) when some students were still arriving at school.

The victim, a 15-year-old student from the school, was struck in the shoulder area by gunfire and was transferred to a local hospital, said Los Angeles County Sheriff Jim McDonnell in a press conference later in the day.

"The juvenile is currently in stable condition," said the sheriff.

The shooting suspect, who fled the scene after the incident, was arrested at a supermarket by an off-duty police officer and was taken into custody, McDonnell said.

The boy was detained on one count of attempted murder, he added.

The suspect's identity was not immediately released, but authorities confirmed he is a former student at Highland High who had transferred schools within the last month, ABC7 reported.

The incident is the 21st school shooting in the United States this year, according to statistics accumulated by CNN.