OROVILLE, Calif. — A student fired shots inside a high school today and held three students hostage for more than an hour before he was taken into custody, authorities said. No one was injured.

The 17-year-old student initially took about 30 students hostage in a band room at Las Plumas High School. He quickly released most of them, but held three girls for about an hour longer before he was arrested, Captain Jerry Smith of the Butte County Sheriff’s Department said.

The gunman’s only demand to deputies during the standoff was that they “back off,” he said.

Six schools in the Oroville Union High School District were locked down while a deputy talked to the hostile student on a cell phone. Authorities said the teenager fired two shots at random from a handgun.

“We made him realize that the best thing for him and everyone concerned was to release the remaining three hostages,” Mr. Smith said.

The boy’s name was not released because of his age. Mr. Smith said he was a student at the school.

An 18-year-old senior who was in the class, Turbo Her, said other students initially thought it was a joke. “I said, ‘Oh no, this is a real gun,'” Ms. Her said. “The girls were crying and hysterical. He wanted to scare them, to let them know it’s real.”

One shot was fired into the ceiling, Mr. Her said. Eventually, the gunman said that “anyone who’s scared can leave,” and about 26 students left. The gunman kept the hostages behind, Mr. Her said.

Another student, Candace Carey, 18, said she was in algebra class next door to the drama classroom where students were taken hostage. She said she and her classmates crawled out a window to flee.

Parents were directed to an Oroville church to be reunited with their children, and cars were backed up for half a mile leading to the church.

Oroville is 80 miles north of Sacramento.