Specialist officers arrived after being notified shortly before 9.10am, to an address on St John Street.
No suspects were found.
Nobody was injured but store workers were left shaken.
Initial enquiries at the scene have continued and an investigation is underway.
Anyone with information should contact police online, if they are able to, or call 101 quoting incident 785 of 15/10/2021.
Details can be passed anonymously to the independent charity Crimestoppers on 0800 555 111.
