Armed police were called to a street in Beccles on Monday morning after a man threatened another with a gun behind the NatWest bank.
The incident took place shortly after 8am in a car park on Smallgate in the centre of the market town.
The gunman was seen standing in an alleyway when he pointed the gun at another man who was in the car park at the time, and told him to get into the alley.
The victim refused and called police and the suspect was seen to run away in the direction of Fair Close.
Armed police and dog units rushed to the scene as officers searched for the man, and a police guard remained at the scene in the hours after the incident as the search continued for the gunman.
The hunt was still continuing on Monday afternoon for the offender who is described as white, around 5ft 8in tall, and of slim build.
He was wearing a black beany hat, dark clothes and dark glasses at the time.
A Suffolk Police spokesman said officers had no more information about the type of firearm which was used.
•Anyone with information about the incident is asked to contact Lowestoft CID on 101 quoting reference BE/15/794, or Crimestoppers anonymously on 0800 555 111.
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