Lancashire Constabulary said officers were called to the branch at 10.37am on Tuesday (21 September) following reports of a robbery.
Police said a man is alleged to have passed a note to a member of staff, in which he claimed to have a gun and demanded money. No weapon was seen and the man left with a large quantity of cash, said the force.
Officers then attended the same store on Wednesday (22 September) where an individual reportedly brandished a knife, threatened staff, and demanded money, again leaving with a large quantity of cash.
