A police officer suffered serious burns to his face in a suspected gas blast that ripped through a house in Gateshead.
Five others were injured in the incident which blew the roof and front off the single-storey home above the River Tyne in Marian Court.
Police were attending with an engineer and paramedics were on stand-by after a strong smell of gas was reported in the area.
The elderly occupant of the house was being led away by a paramedic wearing protective gear when the blast occurred.
The paramedic shielded the pensioner from the worst of the blast force, a North East Ambulance Service (NEAS) spokesman said.
Three police officers who had got the man out of the small property were hit by the explosion, as was a gas engineer.
The NEAS spokesman said: "There were three police officers injured, two of whom have burns to the head and forearms, and one of them has more severe burns to his face and is in a more serious condition.
"The gas engineer had minor burns."
The officers, paramedic, engineer and elderly resident were taken to the Royal Victoria Infirmary in Newcastle for treatment.
Northumbria Police said the injuries were not life-threatening and the injured officers' families have been informed.
Debris from the blast, including glass, roofing materials and the man's curtains, was thrown up for 60ft on to a green in front of the property.
Superintendent Dave Byrne of Northumbria Police said: "The house has been completely destroyed.
"It has been a sizeable force that has caused the damage."
Officers were met with a strong smell of gas when they arrived, he said, after concerns were raised for the safety of the man in the house.
He could not be sure yet where the officers were when the explosion happened.
He said the officers were trained to deal with hazardous situations and members of the public should call the emergency services in similar circumstances.
One local resident walking his dog said: "You cannot believe people have survived that. The roof's gone and there's debris everywhere."
The injured paramedic was a member of the hazardous area response team who was trained to deal with non-standard 999 calls.
"It's never nice when one of our own is injured and we are obviously thinking about him," the ambulance spokesman said.
"Quite clearly, his quick actions in evacuating people from the property, and the fact he was wearing protective equipment which allowed him to shield this man from the full force of the blast, have helped lessen the injuries that could have occurred."
A Northumbria Police spokesman said: "The Health and Safety Executive have now been informed and will take the lead in this investigation.
"The condition of those in hospital remains the same."