The bodies of five people, including a child, have been recovered following an explosion in a residential area of Plum, Pennsylvania, authorities reported on Monday.
The explosion, which occurred on Saturday in the Pittsburgh metropolitan area suburb, injured at least three, with two having already been released from hospital and the other in a critical condition.
Officials have not yet released the names and ages of the dead, though a reported family member told Pittsburgh's ABC 4 that two were father and son.
“This is just a sad, sad day,” Allegheny County executive Rich Fitzgerald said on Sunday. He said the incident was a “loss that no words can convey”.
The explosion occurred about 10.20am in Rustic Ridge Estates, a development about 30km to the north-east of Pittsburgh.
Footage taken via doorbell camera has been circulated widely online, showing a quiet residential street suddenly rocked by the massive explosion that catapulted debris high into the air.
Two other houses were burnt to the ground.
Fifty-seven firefighters were treated on the scene for minor issues, including heat-related injuries, said Steve Imbarlina, assistant chief of Allegheny County Emergency Services.
The cause of the explosion has yet to be determined.
Mr Imbarlina said the investigation could last “months, if not years”.
The Pittsburgh Post-Gazette reported that two other explosions have taken place at the site in recent years. No one was hurt in a blast last year but another in 2008 killed one.