A three-year-old boy and seven-year-old girl have been killed in a house fire and a woman has suffered life-changing injuries.
The young children died at the scene in St Neots, Cambridgeshire, and two adults were treated by medics amid a massive emergency response.
A 35-year-old woman suffered life-changing injuries, while a 46-year-old man escaped with minor injuries, officials said.
Flames were shooting out of the three-storey family home in Eynesbury, a suburb of St Neots, when the first fire crews arrived at about 7am on Thursday.
Photos show black scorch marks and smoke damage on an exterior wall and around windows on the first and second floors of the home.
Nearby residents raised the alarm after they noticed a “serious house fire” had taken hold of the property in the Knights Park
The cause of the fire is under investigation.
A Go Fund Me page has been set up to help the victims of the blaze.
Fundraiser Gemma Phillips said: “Having only recently been impacted by the devastation caused by the fire of my aunt’s home, my heart completely goes out to this family.
“I can only imagine the suffering they are going through.
“Let’s show them we care by donating to help them through the immeasurable trauma they must be experiencing.”
Neighbour Simona Bagnato wrote on the page: “A house next to ours had an accident. The house is totally burnt.
“As neighbor (sic) I thought to help raising money for this family that have lost everything.
“I know that a little help from each of us will make a difference for these unfortunate people. Thank you for your time.”
Firefighters from stations in Huntingdon, Sawtry, St Neots, Gamlingay and Cambridge responded to the tragic blaze.
Crews from Bedfordshire Fire and Rescue Service also attended.
Investigators remained at the scene on Friday morning.
A fire investigation dog team was involved in the probe.
A Cambridgeshire police spokesperson said: “Emergency services have been at the scene of a house fire in Eynesbury since yesterday morning (December 10) where two children have died.
“It is believed the blaze broke out about 7am at a three-story house in Buttercup Avenue.
“A three-year-old boy and a seven-year-old girl were pronounced dead at the scene, a 35-year-old woman has been taken to hospital with life-changing injuries, while a 46-year-old man has suffered minor injuries.
“The cause of the fire is yet to be established, however police are working with fire investigators to get to the route of the blaze.”
Earlier, the force said: “We were called at 7.16am, Thursday December 10, by the ambulance service reporting a fire at a house in Buttercup Avenue, Eynesbury.
“All three emergency services are in attendance.
“Residents are advised to avoid the area while emergency services respond to the incident.”