Police are hunting a knife-wielding robber thought to be responsible for a string of attacks on female newsagents in Bradford.

Detectives today warned staff to be on their guard in case the man strikes again. He has been linked to three offences in the Bradford North area in the past week.

Each attack has taken place between 4.30pm and 7pm at newsagents where there is apparently a female member of staff working alone.

The man always asks for a pack of Regal cigarettes before producing a knife and demanding money from the till.

Detective Sergeant Andy Croasdale, of Bradford North police, said he was confident the three offences were linked.

He said: "Investigations are still ongoing into each of these crimes and newsagents in the area have been sent the warning as a crime prevention measure.

"People should not be alarmed, because these incidents are still quite rare but newsagents should try to avoid people, especially female assistants, being in the shop on their own."

The first attack took place at 4.55pm at Thackley News-agents in Leeds Road, Thackley, on January 9 and the second incident four days later at Lister's newsagents in Stonehall Road, Eccleshill, at 6.55pm.

The latest incident being linked by police occurred at A and M Weldon newsagents in Undercliffe Road, Eccleshill, on Tuesday at 6.11pm. The man is described as a white male in his late teens to mid-20s and between 5ft 10ins and 6ft 1ins tall. He is slim, clean shaven and has either a pale complexion or a red weather beaten face.

His accent is described as local. The man has generally been casually dressed, usually wearing an anorak with hood.

Anyone with information about these incidents should contact the Eccleshill help desk on (01274) 376059.