(CNN) — A shooting at Sikh temple in the Milwaukee suburb of Oak Creek, Wisconsin, on Sunday, left at least three people wounded and one gunman killed by a police officer, authorities said.

The officer was wounded but “returned fire, and that shooter was put down,” said Bradley Wentlandt, the police chief in nearby Greenfield, who briefed reporters. Wentlandt called it “an ongoing and very fluid situation.”

“At this time, we don’t know if there are additional shooters inside the temple,” he said. SWAT teams were combing through the temple, he said, and he urged television stations not to show aerial footage of the operation while it was under way.

The officer was sent to the Sikh Temple of Wisconsin in Oak Creek, south of Milwaukee, after a 911 call about 10:25 a.m. (11:25 a.m. ET). He killed his attacker despite being shot “multiple times,” and is expected to survive, Wentlandt said.

Some people are believed to be trapped inside, and at least one gunman may still be inside, Alderman Dan Jakubczyk told CNN.

“As far as I know, it is still an active situation,” Jakubczyk said.

Carolyn Bellin, a spokeswoman for Milwaukee’s Froedtert Hospital, said one of three men brought there from the incident was in surgery early Sunday morning, while another was in the surgical intensive care unit. The third was being evaluated in the emergency room. All three were in critical condition.

Kathy Moran, a nursing supervisor at Columbia St. Mary’s hospital in Milwaukee, told CNN that early reports suggested between eight to 20 people had been wounded.

Gurcharan Grewal, president of the Sikh Religious Society of Wisconsin, told CNN that he has heard from multiple people that there were wounded victims still inside the temple and that there may have been multiple perpetrators. Police have sealed off the entire area, he said.

Grewal spoke to CNN from another Sikh temple about 20 miles away, where he said police were on the scene was well.
“We are really vigilant. We are really concerned,” he said.

The temple has a congregation of 250 to 400, according to its website.

“I just want to say this temple was built a number of years ago and there have never been any problems with this temple,” Jakubczyk said. “They’ve been a plus to this city and to my district.”

http://edition.cnn.com/2012/08/05/us/wisconsin-temple-shooting/index.html?hpt=hp_t1