Two people have been arrested on suspicion of murder by police investigating a house fire in which a woman and two children died.
A 20-year-old woman, a boy aged four and a two-year-old girl were pronounced dead by firefighters after the blaze broke out at a property in Maes Y Groes, Prestatyn, on Friday night, a North Wales Police spokeswoman said.
Her 23-year-old partner and her 15-month-old son were taken to hospital by ambulance in a critical condition, she added.
Police confirmed the two people in custody are a 45-year-old man and a 42-year-old woman, who live in a ground floor flat underneath the victims.
Neighbour Adele Gordon described the chaotic moments as the fire took hold: "There were people everywhere. This man came running up the street shouting 'my kids are in there, my kids are in there'.
"People started smashing the windows but the smoke was mad, I've never seen smoke like it. It was thick black smoke bellowing out of the house."
Another neighbour, Mike Foster said: "I can't believe it. I'm just in shock. I didn't even know them but I'm just so upset."
A joint investigation is being carried out by North Wales Fire and Rescue Service and North Wales Police.
A Welsh Ambulance Services spokeswoman said the man and baby were taken to Glan Clwyd Hospital.
The man was later transferred to Whiston Hospital, Merseyside, while the baby was moved to Alder Hey Children's Hospital in Liverpool.
Both were said to be in a serious condition.
Detective Superintendent John Chapman said: "We would appeal for anyone who may have seen anything suspicious in the Maes y Groes area of Prestatyn yesterday evening to get in contact as soon as possible by calling us on 101.
"We are deploying Family Liaison Officers to work closely with the next of kin at this difficult time.
"There is a team of dedicated officers working on specific lines of enquiry in relation to this incident."
He said a "meticulous" forensic investigation of the house was under way that could take up to three days to complete.