Five people, including three children and all thought to be members of the same family, were killed in a house fire in west London, police and the fire service said Monday.

There was no immediate indication what caused the fire at the mid-terraced property in Hounslow near Heathrow airport and a neighbour dismissed suggestions that Diwali fireworks were to blame.

Fire crews and police were called to the prperty at about 10:30 pm (2230 GMT) on Sunday. The bodies of the five victims were discovered inside. A sixth person left the house before the emergency services arrived and a seventh is unaccounted for.

"The family had been letting off fireworks earlier in the evening for Diwali but it was nothing to do with that as it was earlier than the fire," Felica Matei was quoted as telling the Evening Standard newspaper.

The fire destroyed the ground and first floor of the property and was brought under control by 1:25 am on Monday, London Fire Brigade said.