Detective Sergeant Stephen Gardiner said: “We received a report just before 6:10 am that a man had entered the shop brandishing a knife.
“He held a knife to a female staff member, and demanded she open the tills.
“Before leaving the shop with a sum of cash, he threatened another member of staff.
“None of the three staff members were physically injured during the ordeal, however, they have been left shaken.
“The suspect had his face covered and was described as wearing a medium length, puffa-style coat, dark navy or black stripe track bottoms, and black trainers with a white top.
“I am appealing to anyone who was in the area this morning, and has information they believe could assist our investigation to contact Detectives at Musgrave on 101 quoting reference number 150 of 27/03/18.
“Alternatively, information can also be provided to the independent charity Crimestoppers on 0800 555 111 which is 100% anonymous and gives people the power to speak up and stop crime.”