A gunman killed 12 people including a sheriff’s deputy after he walked into a Southern California bar and started shooting late Wednesday night, police said.

The gunman was also killed, Ventura County Sheriff Geoff Dean told a news conference early Thursday, though it was not immediately clear by whom.

An unknown number of people were wounded during the attack at the Borderline Bar and Grill, a country & western venue in the Los Angeles suburb of Thousand Oaks.

“It’s a horrific scene in there,” Dean said. “There is blood everywhere and the suspect is part of that.”

The dead officer was identified as Sergeant Ron Helus, a 29-year veteran of the department, Dean told reporters. Helus and a California Highway Patrol officer were the first to arrive at the bar and went inside just before 11:30 p.m. PST (0730 GMT).

After a lull of about 15 minutes, more officers went inside and found the suspected gunman dead of a gunshot wound. It was not clear whether he killed himself or was killed by officers, Dean said.

The incident came less than two weeks after a gunman with an automatic rifle fatally shot 11 people during sabbath services at a Pittsburgh synagogue. (Reuters)

•Police move through the vicinity of a shooting in Thousand Oaks, Calif., early Thursday, Nov. 8, 2018.