Masked thieves wielding a large knife and a hammer robbed an off-licence in Cheetham Hill.
The robbery happened at the Heywood Wines store on Heywood Street at about 7.10pm on Saturday 8 December 2012.
The shop worker, a 43-year-old man, and his friend, 33, were behind the counter when the three masked offenders burst into the shop.
One was brandishing a hammer, the other a large 10inch knife and the third had a large washing bag. After threatening the two men, one of the thieves jumped onto the counter and begun to load the bag with hundreds of pounds worth of spirits and cigarettes.
After stealing the 43-year-old man's mobile phone by pressing the knife to his neck, his friend ran to the stockroom but was chased by the offender wielding the hammer, which he used to attack the victim during a struggle leaving him with a small cut above his eyebrow. Luckily he was able to push the offender back and shut the door.
The trio stole cash from the till and fled, running down Barnedale Drive.
Police are now appealing to anyone with information to come forward.
The man with the knife was white, wearing dark trainers and trousers and a grey hooded top with a white emblem on the left breast. The man with the hammer was also wearing dark clothing and had black Nike trainers. The third man, with the washing bag, was wearing a red hooded top. All were wearing balaclavas or ski masks.
Detective Constable Paul Shacklady said: "The three men responsible for this cowardly robbery have access to weapons, and clearly do not have any qualms about using violence to get their hands on a relatively small amount of cash, cigarettes and alcohol.
"We need to apprehend these men, not least for the victims who were inside the shop who were subjected to such violence, but to ensure they do not target anyone else.
"I would ask that if anyone has information about this robbery that they come forward and speak to us, in confidence if needed.
"If you suspect who was involved, or you witnessed these men going into or out of the shop, then we need to hear from you as your information could be absolutely crucial."
Anyone with information should call police on 101 or the independent charity Crimestoppers, anonymously, on 0800 555 111.