Two people have been arrested 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.

A 23-year-old man and a 15-month-old baby were taken to hospital by ambulance, she added.

"Firefighters from North Wales Fire and Rescue Service were called to a fire at a property in Maes Y Groes, Prestatyn, at 10pm on Friday, October 20 2012," said the spokeswoman.

"Two fire crews from Rhyl and a crew from Prestatyn attended the incident and firefighters wearing breathing apparatus entered the property."

She did not specify what the arrested pair were taken into custody on suspicion of.

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.

The spokeswoman described the property as a house that had been converted into flats.