Police are investigating after two groups of people were threatened at gunpoint in Bury.
The two incidents happened 24 hours apart and officers are now trying to establish if the two are linked.
The first one happened at about 10.20pm on Thursday 6 September 2012. A couple, aged 18 and 16, were sitting on a bench near to the entrance to Hoyle Park, off Thrush Drive, when three unknown offenders came up to them.
One of them produced what looked like a handgun, pointed the barrel at the 18-year-old man's forehead and demanded he handed over cash. He then hit his forehead with the butt of the gun.
Both him and his girlfriend where then punched and kicked before they managed to run off.
Two of the offenders were male, white and about 19 or 20-years-old. One was about 5ft 2in tall, fat and wearing dark clothing. The second was about 5ft 11in tall, slim, but muscley, with very short dark shaved hair and wearing a dark grey tracksuit top and bottoms with a lighter grey band around the wrist.
The third offender was mixed race, about 5ft 6in tall with short dark hair and wearing a dark tracksuit.
The next day, at about 11pm, two women aged 28 and 25 were approached from behind as they walked along York Street, Bury.
One of the offenders tried to grab one of the women's bags and a struggle ensued. During the struggle the offender produced what looked like a handgun and held it to the victim's head, telling her to let go of the bag.
The offenders then ran off with the bag.
One of the offenders was white, in his early 30s, about 5ft 8in tall with a broad build with short dark hair and wearing a long green/grey hoodie and dark coloured three-quarter length trousers. He spoke with a local accent.
Detective Constable Dave Potter of Bury CID said: "At this stage it is not possible to say for sure if these robberies are linked.
"There are obvious similarities in that they happened within 24 hours and about a mile apart and a handgun appears to have been used on both occasions.
"Regardless of whether they are ultimately linked however, people need to know that we have stepped up patrols in the areas.
"Also, while on the face of it these are very concerning incidents, it is not known whether the firearms were real or imitation.
"Incidents like this are extremely rare in Bury and I want to reassure people that we are taking this extremely seriously."
Anyone with information is asked to call Bury CID on 0161 856 8145 or Crimestoppers on 0800 555 111.