A small fire that damaged a Planned Parenthood facility in Southern California apparently was ignited when someone tossed a container with a flammable liquid through a window, authorities said.

Crews reported the smell of gasoline at the scene of the arson late Wednesday in Thousand Oaks, said Ventura County Fire Capt. Mike Lindbery. Nobody was inside the building when the flames broke out.

Surveillance cameras recorded a suspect wearing a hooded sweatshirt and a face mask, sheriff's Capt. John Reilly said. Arson investigators were examining the video and will test the liquid accelerant.

"The footage is really poor. It's very dark, but the cameras did capture someone," he said.

Planned Parenthood has faced criticism and congressional backlash recently for its practice of supplying tissue from aborted fetuses for scientific research.

"We are no strangers to harassment from those who oppose a woman's right to make her own medical decisions," said Jenna Tosh, president and CEO of the organization's Ventura, Santa Barbara and San Luis Obispo counties chapter, which includes the Thousand Oaks office.

"This attack has been part of an uptick in violence against women's health centers and Planned Parenthood," she told The Associated Press.

Tosh said the Thousand Oaks center provides a range of health care services, including birth control, sexually transmitted disease testing and treatment, and such preventative care as cancer screenings. She said the office sees more than 7,000 patients each year.

Crews alerted by a fire alarm around 11:30 p.m. arrived to find the building's sprinklers had extinguished most of the flames. A rock was apparently used to shatter the window before the container was tossed inside, Lindbery said.

There was more damage from the sprinklers than from the fire itself, officials said.

The office had been vandalized within the last 30 days, when another window was broken, but it wasn't immediately known if the two incidents were connected, Reilly said.

The sheriff's office will increase patrols in the area.

Meanwhile, Tosh said Planned Parenthood hopes to reopen the office by Monday.