Five people – including three children – have died and a person remains unaccounted for after a house fire in west London.
The Metropolitan Police said all five victims are believed to be members of the same family.
Ten fire engines and about 70 firefighters were called to the blaze at a property on Channel Close in Hounslow, just before 10.30pm on Sunday night.
The ground floor and first floors of the mid-terrace house were destroyed and part of the roof was also damaged, while nearby properties were evacuated as a precaution.
It is thought there were seven people inside the house at the time.
Five on the first floor of the building were pronounced dead at the scene.
A man managed to get out of the house before the emergency services arrived and he was taken to hospital.
One person – an adult – remains missing, police said.
The cause of the fire – which was brought under control by 1.30am on Monday – is being investigated by the London Fire Brigade and Met Police.
Chief Superintendent Sean Wilson told reporters at the scene: “This is truly a terrible incident. The loss of so many lives will cause unimaginable distress to the family and friends, and the communities, of all those involved.”
He added: “I know that people across the country will be shocked and saddened by this terrible event last night.
“Now ,everyone will want to know why this tragedy occurred and we will be working tirelessly with our colleagues in the London Fire Brigade to find those answers.
“At this time we have an open mind as to the cause of the fire and I would ask people not to add to that uncertainty by speculating.”
Asked if he could rule out fireworks as a possible cause of the fatal blaze, he replied: “At this stage, this is being investigated both by ourselves and specialist fire officers.
“I am not ruling anything out, I don’t think we are in a position to do that.
“We keep an open mind, it is such an early stage and there is an awful lot of work to be done.”
London Fire Commissioner Andy Roe said: “This is a terribly sad incident and the thoughts of all of us at London Fire Brigade are with the family, friends and all those affected at this difficult time.
“Staff will be in the local community today to offer support and advice where needed.
“The welfare of our staff is very important and all those involved will be offered support from our counselling and trauma service.”
Labour MP Ruth Cadbury, whose constituency includes Hounslow, wrote on X, formerly Twitter: “I am devastated to learn this morning that 5 people, including children, died in a fire in a house in Hounslow last night.
“My thoughts are with their family, friends neighbours.”