A California university has placed two campus police officers on administrative leave over the use of pepper spray against students taking part in a protest in support of the Occupy Wall Street movement.

Linda Katehi, the chancellor of University of California Davis, where the incident occurred, said on Sunday that she shared students' outrage and set a 30-day deadline for a task force investigating the incident to report its findings.

Katehi has faced calls to resign over the Friday incident, captured on video and circulated on the internet, in which police in body armour doused a line of protesters in pepper spray as they sat in a line.

Nine students doused with pepper spray were treated at the scene, two were taken to hospitals and later released, university officials said. Ten people were arrested.

"I am deeply saddened that this happened on our campus, and as chancellor, I take full responsibility for the incident," said Katehi.

"However, I pledge to take the actions needed to ensure that this does not happen again. I feel very sorry for the harm our students were subjected to and I vow to work tirelessly to make the campus a more welcoming and safe place."

Mark G. Yudof, the president of the University of California, said on Sunday he was appalled by the images.

"I implore students who wish to demonstrate to do so in a peaceful and lawful fashion. I expect campus authorities to honour that right,'" Yudof said.

The identities of the two officers were not revealed, but the campus police chief told the Associated Press news agency that one was a veteran of the school's police force, while the other was "fairly" new to the department.

``We really wanted to be diligent in our research, and during our viewing of multiple videos we discovered the second officer,'' said Annette Spicuzza, the police chief.

The protest was held in support of the overall Occupy Wall Street movement protesting against economic inequality and in solidarity with protesters at the University of California, Berkeley, where police used batons to break up Occupy-inspired camps on November 9.