An explosion rocked a Wisconsin community after a contractor struck a natural gas main in a downtown area filled with bars and other businesses, injuring two firefighters and a police officer, authorities said.

Firefighters and police officers responded to a reported gas leak, and an evacuation was underway when the blast happened Tuesday, said Sun Prairie police Lt. Kevin Konopacki.

He added that lives were likely saved as a result of the evacuation.

No deaths were reported, but Konopacki said buildings would be searched in the Madison, Wisconsin, suburb of about 30,000 once the flames were out.

Firefighters were still battling flames more than three hours after the explosion.

The powerful blast around 7:15 p.m. (0015 GMT) sent a plume of smoke and flames into the air.

Konopacki said the firefighters were taken to a hospital, while the officer was treated at the scene.

He said some civilians suffered minor injuries, but none required hospitalization. He didn't know the exact number of civilians hurt.

WE Energies spokeswoman Amy Jahns said workers for a contractor apparently punctured a 4-inch natural gas main, sending gas leaking into a building ahead of the explosion.

All 12 gas lines in the area were shut off by about 9:30 p.m. local time (0230 GMT).

The blast about half a block from City Hall appeared to be centered on the Barr House, a pub.

Authorities evacuated a half-mile radius and set up a shelter at Sun Prairie High School.

Residents of an assisted living facility are being allowed to shelter in place.