A 16-year-old student, armed with a shotgun, walked into a rural California high school on Thursday and shot one student and fired at others and missed before a teacher and another staff member talked him into surrendering, officials said.

The teen victim was in critical but stable condition, and the suspect, whose pockets were stuffed with ammunition, was still being questioned, Sheriff Donny Youngblood said at a news conference on Thursday.

The suspect used a shotgun that belonged to his brother and went to bed on Wednesday with a plan to shoot two fellow students, Youngblood said.

When the shots were fired, teacher Ryan Heber tried to get the more than 24 students out a back door and engaged the shooter in conversation to distract him, Youngblood said. Campus supervisor Kim Lee Fields responded to a call of shots being fired and also began talking to the teen.

"They talked him into putting that shotgun down. He in fact told the teacher, 'I don't want to shoot you,' and named the person that he wanted to shoot," Youngblood said.

He said the suspect alleges the two students who were targeted had bullied him for more than a year, but the sheriff couldn't confirm the allegations.

He did not release the student's disciplinary record, saying he didn't have it. The shotgun is believed to belong to the boy's brother and was in the boy's home, Youngblood said.

Trish Montes, who lived next door to the suspect, said he was "a short guy" and "small" who was teased about his stature by many, including the victim.

Montes said her son had worked at the school and tutored the boy last year, sometimes walking with him between classes because he felt sorry for him.

"All I ever heard about him was good things from my son," Montes said. "He wasn't Mr Popularity, but he was a smart kid. It's a shame. My kid said he was like a genius. It's a shame because he could have made something of himself."

Wilhelmina Reum, whose daughter Alexis Singleton is a fourth-grader at a nearby elementary school, heard of the attack while she was about 56 km away in Bakersfield and immediately sped back to Taft.

"I just kept thinking this can't be happening in my little town," she said.