Oak Creek, Wisconsin (CNN) -- At least seven people, including a gunman shot by a police officer, were killed Sunday in an attack on worshippers at a Sikh temple in the Milwaukee suburb of Oak Creek, police 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. Investigators who picked through the building afterward found four bodies inside the temple and two other victims outside, plus the gunman, Wentlandt said.
At an afternoon news conference, Oak Creek Police Chief John Edwards said that authorities are treating the shooting as a "domestic terrorist-type incident," adding that the FBI will head the investigation.
Two semi-automatic handguns believed used by the shooter were recovered from the scene, a law enforcement source directly involved in the investigation told CNN.
At least three wounded, including the officer, were being treated at Milwaukee's Froedtert Hospital, spokeswoman Carolyn Bellin told CNN. All three were in critical condition.
Edwards said late Sunday afternoon that officers "just were able to clear" the scene of the shooting at the temple.
Family members gathered outside the temple, or gurdwara, told CNN affilliate WTMJ that survivors were being taken to a nearby bowling alley for questioning. Amardeep Kaleka said his father, congregation president Satwant Kaleka, was shot and wounded when he attempted to tackle the gunman, and his mother -- who hid in a closet during the violence -- was too distraught to talk.
And Darshan Dhaliwal, another of the gurdwara's leaders, said Sunday afternoon he wasn't sure how many were hurt.
"Our dear ones and near ones are injured and hurt, and we are trying to find out what happened," Dhaliwal told WTMJ.
And another man told the station, "Nobody's angry here. We're just confused. Was this a random act? Was this directed at us because of the way we look?"
The Sikh religion originated in northern India in the early 1500s. Sikh men are identifiable by their beards and turbans, but often confused for Hindus or Muslims. There are roughly 25 million Sikhs in the world, 700,000 of whom live in the United States, according to the Sikh American Legal Defense and Education Fund.
The Oak Creek gurdwara 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," Oak Creek Alderman Dan Jakubczyk said. "They've been a plus to this city and to my district."
Though early reports had suggested there may have been more than one attacker, Wentlandt said officers had not identified any other gunmen. As the search went on, utility crews cut electric and gas service to the building at the request of authorities, said Cathy Schulze, a spokeswoman for area utility We Energies.
The police officer wounded in the assault is a 20-year veteran who was shot multiple times, Wentlandt said, but he was expected to survive. 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).
State Rep. Josh Zepnick, who represents much of the Milwaukee area's Sikh community, said he was "torn to shreds" by the attack.
"It's a very peace-loving community that has successfully integrated and assimilated into the metropolitan Milwaukee area," Zepnick told CNN afilliate WTMJ.
And state Rep. Mark Honadel, who represents the area, called the attack "craziness."
"Unfortunately, when this type of stuff hits your area, you say to yourself, 'Why?' But in today's society, I don't think there's any place that's free from idiots."
Top state and national political leaders offered statements of condolence after the killings, which came two weeks after a massacre at a Colorado movie theater that left 12 dead and dozens more wounded.
"Our hearts go out to the victims and their families, as we all struggle to comprehend the evil that begets this terrible violence," Wisconsin Gov. Scott Walker said in a statement issued by his office. "At the same time, we are filled with gratitude for our first responders, who show bravery and selflessness as they put aside their own safety to protect our neighbors and friends."
In a statement from the White House, President Barack Obama said the United States had been "enriched" by Sikhs, "who are a part of our broader American family."
"My administration will provide whatever support is necessary to the officials who are responding to this tragic shooting and moving forward with an investigation," Obama said.
And from Boston, Obama's presumptive Republican challenger, Mitt Romney, called the slayings "a senseless act of violence and a tragedy that should never befall any house of worship." He said the hearts of he and his wife, Ann, "are with the victims, their families, and the entire Oak Creek Sikh community."