LONDON -- A woman and three children died on Wednesday in a house fire in Bradford, the United Kingdom (UK). Police believe the fire was "started deliberately."

Emergency services arriving at the scene of the fire in the early hours of Wednesday found a 29-year-old woman who had already died. Three children - two girls and a boy - were taken to hospital, but later died from injuries sustained in the fire.

A 39-year-old man was arrested at the scene on suspicion of murder, and taken to hospital with critical injuries.

"Whilst inquiries are at their early stages, we believe that the fire was started deliberately and this incident was domestic-related," Superintendent Lucy Leadbeater of West Yorkshire Police told reporters.

She said a murder investigation has been launched.