By Pamela Bilalova, BBC News, North East and Cumbria
A man has been seriously hurt and a dog has been killed in a house explosion.
Emergency services were called to Coronation Terrace in Willington, County Durham, at about 01:30 BST.
Durham Police said a man in his 40s suffered “serious injuries” and was taken to the Royal Victoria Infirmary (RVI) in Newcastle for treatment.
The force added a young German Shephard “tragically” died.
Nearby residents were told to leave their homes “as a precaution”, with the affected property cordoned off.
Police confirmed most residents have been allowed to return to their homes on Monday evening.
People are being advised to avoid the area.
“A cordon remains in place around the scene while police and fire investigators work to establish the cause,” a spokesperson said.
The force also appealed for anyone with information to contact police, and asked people not to speculate on the circumstances.
Residents have spoken of their shock at the blast, which destroyed the house.
Next-door neighbour Hannah Wright said she woke up to the sound of “a massive explosion”.
“The house was gone,” she told the BBC.
“Just horrendous. We had to get the children out… because there was gas leaking.”
County Durham and Darlington Fire and Rescue Service said an investigation would take place “in due course”.
Group manager Chris Williams said: “Our crews will remain in the area today alongside colleagues from Durham Constabulary, Durham County Council and Northern Gas Networks to assess the site and ensure it is structurally safe.”