The Associated Press reported at least seven people were killed at a Sikh temple outside Milwaukee on Sunday, one of whom was the gunman. 

The still-unidentified suspect shot four people in the Sikh Temple of Wisconsin in Oak Creek then shot two more outside, the Washington Post reported. He was then killed by a police officer who was shot several times in the exchange. He, along with two other wounded, are being treated at Froedtert Hospital in Milwaukee. 

Harpreet Singh, a witness from the scene, estimated there had been 30 to 35 people in the building when the shooting began. 

Authorities are treating this as a "domestic terrorist-type incident" according to a CNN report, and the FBI will be heading the investigation. 

Greenfield police chief Bradley Wentlandt said officers had not identified any other gunmen. 

There have been several anti-Sikh hate-crimes in the last year, The New York Times reported. According to a letter New York Representative Joseph Crowley sent to Attorney General Eric Holder, two Sikh men were murdered in Sacramento, a Sikh temple in Michigan was vandalized, and a Sikh man was beaten in New York. 

While the Post reported no motive had been officially established for the shooting, Crowley is urging data to be collected on anti-Sikh violence. 

Both President Obama and his Republican challenger Mitt Romney released statements expressing their condolences Sunday afternoon.