An employee at a Ramsbottom off-licence was hit over the head with a handgun by a masked man during a robbery on Sunday.
Two masked men entered Bargain Booze in Bolton Road West at 7.20pm, threatening staff and demanding money.
One of the men then hit a member of staff over the head with a gun, and took cash from the till.
The pair then left the store in the direction of Ramsbottom town centre.
It is understood that the member of staff was not badly hurt.
One of the men wore a white ‘V for Vendetta’ mask, and is described as being in his early 20s, 6ft tall and having a slim build.
He wore a black tracksuit jacket with a hood up, light blue jeans with scuff marks, and grey or blue deck shoes with white laces.
The other man is described as slim and wearing a dark grey Adidas hooded top, white and grey jogging trousers and black trainers.
Police are appealing for witnesses.
Detective Sergeant Alison Byrne said: "The man was not badly injured but the men did manage to get away with the cash.
"We are urging anyone who was in the area and remembers seeing the men described to get in touch with police."
Anyone with information is urged to call police on 0161 856 8181 or Crimestoppers anonymously on 0800 555 111.