A former police officer killed three people and wounded six others when opening fire at a famed biker bar in Southern California before he was shot dead by police late on Wednesday, officials said.

The shooter went into the bar targeting his ex-wife, who was wounded but survived, local media including the Los Angeles Times and the Orange County Register reported, citing law enforcement sources. She had been a regular at the bar and its weekly $8 spaghetti night, they said.

The gunfire occurred at Cook's Corner in Trabuco Canyon, about 50 miles (80 km) southeast of Los Angeles, shortly after 7 pm local time as dozens of patrons were at the 140-year-old establishment beloved by motorcycle riders and enthusiasts.

"It's an absolute tragic event," Orange County Undersheriff Jeff Hallock told a news conference late Wednesday night.

"This I know is probably weighing very heavy on the entire Trabuco Canyon community. Cook's Corner is a staple in South Orange County."

Deputies raced to the scene after receiving emergency calls that shots were being fired at the bar. They confronted a male gunman, who was killed during an officer-involved shooting, Hallock said.

Three other people were pronounced dead at the scene. Paramedics took six others to the hospital, five of whom suffered gunshot wounds, Orange County Fire Chief Brian Fennessy said.

Two of the six were in critical condition and the others were in stable condition, he said.The Ventura Police Department in a statement identified the shooter as retired Sergeant John Snowling, who served from July 1986 through February 2014 in the city about 80 miles (130 km) northwest of Los Angeles.

Ventura police were cooperating with the Orange County Sheriff's Department in the investigation, police said.

"Our hearts weigh heavy with the distressing incident at Cook's Corner," Ventura Police Chief Darin Schindler said in the statement. "Our deepest condolences are with the families of the victims, the survivors, and the Orange County deputies who swiftly responded to the scene."

The office of California Governor Gavin Newsom said it was monitoring the shooting. President Joe Biden had been briefed on the situation, according to the White House.