A gunman has opened fire in a southern California church, killing one person and wounding five others before churchgoers detained the suspect and hog-tied him in what officials called an act of “exceptional heroism”.

The shooting was reported shortly before 1:30pm on Sunday (20:30 GMT) at the Geneva Presbyterian Church located in the town of Laguna Woods, about 80 kilometers (50 miles) southeast of Los Angeles, the Orange County Sheriff’s Department said on Twitter.

A man died at the scene and four others were critically wounded, while a fifth injured person suffered minor injuries, officials said.

All the victims were adults.

Jeff Hallock, the Undersheriff for Orange Country, said when deputies arrived the parishioners had the suspected gunman hog-tied.

The suspect, an unidentified man in his 60s, is now in police custody.

“That group of churchgoers displayed … exceptional heroism and bravery in intervening to stop the suspect. They undoubtedly prevented additional injuries and fatalities,” said Hollack.

About 30 to 40 people were in the church when the shooting occurred, Hallock said, and two handguns were found at the scene.

“At this time, we do not know what the suspect’s motive may be or whether he had an intended target, or whether this is even a hate-related incident,” Hallock said, adding that authorities believe the suspect does not live in the area.

He said the many unanswered questions include whether the assailant attended the church service, if he was known to church members and how many shots were fired.

‘Upsetting and disturbing news’

The shooting occurred at an afternoon lunch reception honouring a former pastor of a Taiwanese congregation that has services at Geneva, according to a statement from the Presbytery of Los Ranchos, a church administrative body.

“Please keep the leadership of the Taiwanese congregation and Geneva in your prayers as they care for the those traumatized by this shooting,” the presbytery’s Tom Cramer said in a statement on Facebook.

Carrie Braun, a spokeswoman for the sheriff’s office, said the majority of those inside the church are believed to be of Taiwanese descent.

Investigators were looking at many factors, including whether the bloodshed could be a hate crime, she said.

Federal agents from the Bureau of Alcohol, Tobacco, Firearms and Explosives were responding to the scene. The FBI was also sending agents to the scene to assist the sheriff.

The incident occurred in an area with a cluster of houses of worship, including Catholic, Lutheran and Methodist churches and a Jewish synagogue.

California Governor Gavin Newsom’s office said on Twitter that he was closely monitoring the situation.

“No one should have to fear going to their place of worship. Our thoughts are with the victims, community, and all those impacted by this tragic event,” the tweet said.

A man reads scripture at the site of a memorial — The shooting came a day after an 18-year-old white gunman targeted a supermarket in a black neighbourhood in Buffalo, New York state, killing 10 people [Joshua Bessex/AP Photo]

The shooting came a day after an 18-year-old white gunman opened fire at a supermarket in a black neighbourhood in Buffalo, New York state, killing 10 people.

“This is upsetting and disturbing news, especially less than a day after a mass shooting in Buffalo,” tweeted Democratic Congresswoman Katie Porter, who represents Orange County in Washington.

“This should not be our new normal.”

Laguna Woods was built as a senior living community and later became a city. More than 80 percent of residents in the city of 18,000 people are at least 65.

The shooting throws the spotlight on mass shootings that have become a sadly familiar scene across the US. (Text, excluding headline: Al Jazeera and News Agencies)

•PHOTO: Authorities in California have not made any statement regarding a possible motive in the church shooting [David Swanson/Reuters]

Update news