Detectives are appealing for information following the terrifying ordeal in the Springburn area of Glasgow on Monday.
Around 1.30am two men entered the Phoenix Filling Station on Keppochill Road and one of them presented what appeared to be a handgun at the female member of staff.
The pair left the premises with a three figure sum of cash and headed in the direction of Cowlairs Park.
The first suspect, who was holding the handgun, is described as white, 5ft8, and wearing black Adidas jogging bottoms with royal blue stripes down the sides, a black jacket with the hood up covering his face and a black glove on his left hand with a white motif, possibly a Nike tick.
He was also wearing light grey Nike canvas trainers white a white Nike Tick and white sole and carrying a silver carrier bag with white writing.
The second suspect is described as white and wearing a navy blue crosshatch puffa jacket an orange/red zip, orange hood lining and a noticeable rip on the right shoulder at the back with white padding sticking out. He was also wearing a black hooded top under the jacket which covered most of his face and black North Face tracksuit bottoms with a white logo on the left thigh and white calf.
Detective Constable John Tweedle from the Community Investigation Unit based at Govan said: “This was a terrifying ordeal for the woman working in the petrol station at the time and it is absolutely vital that we trace the despicable individuals involved.
“I would appeal to anyone who was in the surrounding area in the early hours of Monday morning and noticed two men matching the above descriptions, or anything at all suspicious, to please get in touch.
“Anyone with information is asked to contact the Community Investigation Unit based at Govan via 101, quoting incident number 0148 of Monday 10 September 2018. Alternatively you can call CRIMESTOPPERS on 0800 555 111 where details can be given in confidence.”