A gunman has opened fire at a campground near Temecula, California, injuring at least three people at a Korean Christian retreat, local media news reported on Wednesday.

Details of the incident were sketchy, but a spokesman for the Riverside County Sheriff's Department said investigators believe a suspected gunman may be among the injured at the retreat in the hills outside Temecula, The Los Angeles Times reported on its website.

Earlier reports quoting a sheriff's department spokesman at the scene said one of those shot had been killed, but the Times said that claim could not be confirmed by other officials.

The Riverside County sheriff's office, which covers Temecula, in southern California, did not immediately confirm details when contacted by AFP.

The Times quoted sheriff's deputy Herlinda Valenzuela as saying a report of an assault with a deadly weapon was received at 7.23 pm (0223 GMT).

"Initial reports were that there were several victims," the Times quoted her as saying. "Two people with gunshot wounds were found initially and transported to the hospital."

Investigators searching in the dark found two more victims ? apparently in critical condition ? the Times quoted Valenzuela as saying.

The rampage ricked the Kkottongnae Retreat Camp, run by the Congregation of the Sisters of Jesus, a Christian social service.

Sheriff's department spokesman Dennis Gutierrez told the Times investigators did not think gunman was at large.

The language barrier

"Because of the language barrier, we don't know who the shooter is yet. But we feel there is no one out in the community who is armed," Gutierrez said.

The California shooting came just hours after a gunman in Alabama shot dead his wife, daughter and two other people before killing himself.

It was the latest in a surging wave of recent murder-suicides that have shocked the United States, where gun ownership is a constitutionally guaranteed right.

The body of Kevin Garner, 45, was found Tuesday near the home he formerly shared with his estranged wife in Morgan County, Alabama.

Law enforcement agents said Garner had earlier gunned down his wife, his daughter a sister and her nephew in the town of Greenhill, news reports said.

The killings came ahead of a divorce hearing between Garner and his wife Tammy due to take place on Wednesday.

Garner's sister had been due to testify on behalf of his estranged wife at the hearing, the Times Daily newspaper reported on its website.

Last weekend a man in Washington state shot dead his five children before killing himself after discovering his wife was leaving him.

On Saturday three police officers were killed by a 23-year-old man at his home in Pittsburgh, Pennsylvania.

That incident came a day after a recently unemployed man stormed an immigrant services center where he had been learning English in Binghamton, New York and went on a rampage, killing 13 people before taking his own life.

On March 29, a heavily armed gunman shot dead eight people at a North Carolina nursing home, days after six people were killed in a murder-suicide in an upscale neighborhood in northern California's Silicon Valley.

And on March 10, an unemployed man killed his mother, grandmother and eight others on a vicious shooting rampage in Alabama.