A gas explosion at a house in Nottingham was so loud it sounded like a bomb, a witness has said.
Fire crews were called to the house on Stockhill Lane, Stockhill, shortly before 2100 BST on Sunday.
A woman in her 40s and a man in his late 30s, who were rescued from the rubble, are being treated for serious multiple injuries, including burns.
A number of houses were evacuated. Eyewitness Ken Hamilton said: "It was like a bomb going off."
Mr Hamilton was near the street when the explosion happened and pulled two girls to safety.
He said: "I came running to the main road, two young girls were screaming and I realised they were in the back garden and managed to lift them over the next door neighbour's fence to get them out.
"It was like a bomb going off, it was that loud."
Police confirmed two children, aged 10 and 13, were taken to hospital, although they were not injured.
At this stage it is not whether they were inside or outside the house at the time, officers said.
Stockhill Lane was closed throughout the day. A window frame was blown into the road while other debris landed in a neighbouring park.
A Nottingham Fire and Rescue Service spokesman said the rear of the house collapsed and the roof was "severely damaged" by the blast.
The building will require scaffolding support to make it safe enough to enter and an assessment of the building is expected to be carried out on Tuesday.
Nottingham City Homes, which manages 29,000 properties in the city, confirmed it had fitted a new boiler at the address six weeks ago.
Officers added they were keeping an open mind about the cause of the incident.