An explosion at a city centre house is being treated as suspicious by police.
The blast happened at about 02:00 BST at a property on St Nicholas Road in the St Paul's area of Bristol.
A neighbour described how his house "filled with smoke" and his children were crying before firefighters arrived to evacuate them.
There have been no reports of any injuries but neighbouring homes have been evacuated as a precaution, and roads closed.
An Avon and Somerset Police spokesman said: "An investigation is ongoing to determine the cause of the incident but at this early stage we are treating it as suspicious."
Uthayakumar Kuddithamby, who lives next door, said fire crews "saved his life".
"We were told to go outside by the fire team, who were very quick,"
Mr Kuddithamby said he saw a man running away from the back garden of the property shortly after the blast woke him.
He said he thought the house was empty and up for sale.
Gas and electrical engineers are at the scene and there are road closures from St Nicholas Road and its junction with Grosvenor Road.
A diversion route has been set up via Ashley Road and police have advised people to avoid the area while the emergency services remain on site.