Washington, Nov 8 (IANS): At least 11 people, including a police officer, have been injured after a gunman forced his way into a popular bar in the US state of California and opened fire.

Police officers responded to the incident at the Borderline Bar and Grill in Thousand Oaks at about 11.30 p.m. on Wednesday (0730 GMT Thursday). Ventura County Sheriff's Office Captain Garo Kuredjian said it was not yet known how seriously injured the victims were, CNN reported.

The authorities said the shooter was dead inside the venue and there were at least 200 people inside the bar attending a college country music night at the time of the incident, media reports say.

At least one officer called to the scene was injured. Officers said approximately 30 shots had been fired, Ventura County Star reported.

Witnesses described a scene of panic in the bar when the gunman started firing. Some said they used chairs to break windows to escape while others sheltered inside toilets.

According to reports, the suspect may have used smoke grenades and at least one gun during the attack.

"A gentleman, who walked in through the front door, shot the girl that was right behind the counter," said Holden Harrah, who witnessed the shooting.