Two people have been arrested by police investigating a house fire that killed a woman and her two children in Maes Y Groes, Prestatyn, North Wales, on Friday night.
Police say two other people were taken to hospital after the blaze broke out at a house in the town.
A spokeswoman for North Wales Police said a 20-year-old woman, a boy aged four and a girl aged two were pronounced dead by firefighters.
A 23-year-old man and a 15-month-old baby were taken to hospital by ambulance, she added.
A joint investigation has been launched by North Wales Fire and Rescue Service and North Wales Police.
Welsh Ambulance Services spokeswoman said the man and baby were taken to Glan Clwyd Hospital.
Both were said to be in a serious condition.