Nine people have been injured by a gas explosion which destroyed a row of homes and left firefighters battling to establish if anyone was trapped in the rubble.
The blast tore through the terraced properties in Irlam, Salford, Greater Manchester, shortly before 7.15am, spraying passers-by with flying glass.
Residents in Merlin Road reported waking up to a massive "booming noise".
A North West Ambulance spokesman said one woman in her 70s was in a critical condition after being taken to Wythenshawe Hospital with 30% burns.
Two adults and three children were taken to Salford's Hope Hospital with minor injuries.
Three other people were treated at the scene for minor wounds - two were hit by flying glass and debris and one man was injured when his ceiling collapsed.
"The only serious injury is the elderly lady and we have no information about people possibly unaccounted for," said the spokesman.
Police, paramedics and more than 40 firefighters were involved in the operation, along with dogs from the fire brigade's Urban Search and Rescue Team.
Nearby Fiddlers Lane Community Primary School was closed to pupils but opened to help evacuated residents.
Teams from National Grid, which owns and operates the gas pipes, were in the process of isolating the gas supply to Merlin Road.