The cause of the fire, which began on Thursday evening, is unknown; the victims are thought to be related.
Four young children have died in a house fire in Sutton, south London, the fire service has said.
Eight fire engines and 60 firefighters attended the fire in Collingwood Road on Thursday at around 18:55 GMT.
The four children – thought to be related – were given immediate CPR by firefighters, who continued to give treatment until ambulance crews arrived.
The children were taken to hospital, where they were pronounced dead.
No arrests have been made, and the cause of the fire is unknown.
London Fire Commissioner Andy Roe said the deaths had “left everyone numb with profound sadness”.
Firefighters in breathing apparatus battled an “intense” blaze throughout the entire ground floor of the mid-terrace property, the London Fire Brigade added.
After finding the children inside the house, crews brought them outside where they were given “immediate emergency care”.
The London Ambulance Service said a “number of resources” were sent to the scene including ambulance crews, advanced paramedics, and trauma teams from London’s Air Ambulance and Air Ambulance Kent Surrey Sussex.
It said the children were treated at the scene before being taken to two south London hospitals where they died.
The blaze was under control by 20:36, with the cause currently unknown and under investigation.
The Metropolitan Police said the four children are thought to be related, with their next of kin aware of their deaths and due to be given specialist support.
The force added that road closures are in force as emergency services remain at the scene, and that officers would be “working through the night and beyond”.
Superintendent Rob Shepherd said: “At this very early stage the cause of the fire is unknown and will be investigated.”