A firefighter has been killed in the US state of Wisconsin and at least a dozen other people were injured when a natural gas explosion levelled two buildings.
Another firefighter suffered critical injuries after fire crews arrived to investigate a gas leak and several buildings exploded, igniting a fire that sent billowing smoke that could be seen for miles around.
Four other firefighters, a police officer and seven civilians suffered injuries, say police.
WE Energies spokeswoman Amy Jahns said workers for a private contractor punctured a four-inch gas main, causing a leak that resulted in the explosion which rained debris around the downtown area and ignited vehicles parked in the area.
Authorities evacuated a half-mile radius around the centre of the explosion. The Barr House and Glass Nickel Pizza shop exploded after the gas ignited, police said.
Local Steve Owen said he saw firefighters and police officers on the street and then the explosion happened. He said the building across from his shop "literally lifted up."
He said the force of the blast knocked him back in his chair and that he ran outside and saw a ball of fire.
"People were scrambling," said Owen, who lives above his shop.
Jill Thompson, 56, who lives about two blocks away, said she saw smoke immediately after the blast occurred.
"It shook the whole building," Thompson said. "I thought someone had hit the building with their vehicle."
