CALIFORNIA: At least four people were killed and nearly a dozen people were wounded, including three young children, when a shooting broke out Tuesday at a school in rural northern California.

Assistant Sheriff Phil Johnston told the KCRA news network that the assailant was killed by police following the shooting, which began around 1600 GMT at a home in Tehama County and continued at the Rancho Tehama Elementary School.

Local news reports said the incident began as a domestic dispute that escalated.

Jim Schultz, a reporter for the Redding Record Searchlight newspaper, quoted Rancho Tehama resident Salvador Tello, who was taking his three children to school and described seeing the gunman open fire, killing a woman.

"He said he saw bullets strike the truck in front of him and he put his children down to protect them and put his truck to... reverse," Schultz said on Twitter.

"As he left, he saw (a) woman lying dead in the street and her... wounded husband next to her. Was told help was on its way."

Schultz quoted another witness, Casey Burnett, who said the gunman was "driving around and shooting randomly from his car."

Area resident Brian Flint told local media that his roommate had been shot and killed by the gunman, a former convict in his 50s.

"He's dead. He didn't make it," Flint told KCRA, referring to his roommate. "For his family and everything, I feel bad, and we'll be there for them."

He said the gunman was a neighbour and had "been shooting a lot of bullets lately, hundreds of rounds, large magazines."

"We made it aware that this guy is crazy and he's been threatening us," he said.

The shooting coincides with a new flare-up of the long-running debate on America's epidemic of gun violence and the ready accessibility of high-powered weapons, less than 10 days after a gunman shot dead 26 people at a church in Texas.