Bradford fire: Man of 21 still quizzed (VIDEO)

It is not known how the fire in the early hours of yesterday began at their home although police have appealed for witnesses who saw anyone buying small amounts of petrol on Monday night to get in touch.

Residents on the council estate told how they were woken up at about 12.30am by sounds of screaming and saw the mother-of-two, named locally as Iram Shah, rolling around on the small patch of grass in front of her house.

In spite of their frantic efforts to douse the flames and the fire service's arrival in just over three minutes it was all to no avail as Aleena Shah, 10, and her eight-year-old brother Aman died.

Post mortems will be held today followed by formal identification of the bodies.

The 30-year-old mother is being treated for life threatening injuries at Pinderfields Hospital, Wakefield.

A spokesman for West Yorkshire Police said a 21-year-old man had been arrested in connection with the fire and he remained in police custody.

He said: "Police and West Yorkshire Fire and Rescue Service have launched a joint investigation in order to establish the full circumstances."

Senior Investigating Officer Det Supt Bill Shackleton said: "I am appealing for anyone with information about the fire to come forward. Two young children have lost their lives and it is crucial we establish how and why the fire started."

Station manager Chris Clarke, who leads the West Yorkshire fire investigation team, said neighbours performed heroics trying to get into the house.

But he said even fully-equipped firefighters were "on the edge" because it was an "extremely severe fire".

Police and firefighters were called to the house at about 12.40am on Tuesday. Many of the homes surrounding it are boarded up awaiting demolition and people living nearby said the abandoned buildings have been plagued by arsonists in recent weeks.

Detective Superintendent Bill Shackleton of West Yorkshire Police said: "I would particularly like to speak to anyone who may have information about anyone buying petrol in small cans in the Bradford area either yesterday evening or in the early hours of this morning."