A gunman opened fire at a Korean Christian retreat center, leaving one woman dead and four people injured, authorities said.

The gunman, described as an Asian man in his 70s, was among the wounded, Riverside County Sheriff's Sgt. Michael Lujan told KNBC-TV on Wednesday.

Authorities were first called to the rural area about 7 p.m. Tuesday after receiving reports about a man shooting his wife, California Highway Patrol spokesman Mario Lopez said.

The identity of the dead woman was being withheld until relatives were notified. In addition to the gunman, two men and a woman were hospitalized.

Investigators were still trying to learn the circumstances of the shootings, and were hindered since many of the victims speak only Korean, Riverside County Sheriff's spokesman Dennis Gutierrez said.

"That language barrier, that's the key to figuring out what happened," Gutierrez said.

The Kkottongnae Retreat Camp, located in Temecula about 85 miles southeast of Los Angeles, is one of four U.S. branches of the Kkottongnae Brothers and Sisters of Jesus, a Roman Catholic organization dedicated to serving the poor and homeless. It was founded in the city of Cheongju, South Korea, by Father Oh Woong Jin in 1976.

Kkottongnae means "flower village" in Korean.

A woman who answered the phone at the group's Lynwood branch on Tuesday night said she did not speak English well and declined to discuss the shooting.

At the group's headquarters in Eumseong, South Korea, south of Seoul, spokesman Brother Matthew Park said Wednesday he has been unable to get through to branch officials in California and only learned about the shooting through news reports.

The campground, previously used as a summer camp before the group bought it, was marked by a single white sign in English and Korean on the side of a rural winding road in remote southeast Riverside County. The retreat was a mile up a narrow road into the hills.

"We have some nuns that are very distraught," Gutierrez said.

Deputies had evacuated the campground and blocked off access. Nothing could be seen from the main road.

Several women from the retreat sat wrapped in blankets outside the law enforcement lines.

"This is the last place this is supposed to happen," Gutierrez said. "A lot of people are shaken up."

Chang Kim, of Los Angeles, stood at the scene, saying his 88-year-old mother lives up the road that was blocked off. Kim said he was concerned because he could not reach her.

"My mother lives up there," he said. "I can't go there. I can't get in. I'm stuck."