A man threatened a shop assistant with a pistol before stealing cash from a store in Shrewsbury.
The robber, who is aged in his 50s, went into the Spar store, on Whitchurch Road, at 2050 BST on Thursday.
He threatened the assistant with a black pistol before stealing cash and visa vouchers.
The shop assistant was uninjured in the attack.
Detective Inspector Robert Mountford, from Shropshire CID, said: "The shop is situated in a busy area and it would still have been fairly light at the time of the incident.
"This man would probably have been outside or near the premises some minutes before in order to pick his moment when the shop was empty of customers."
The man is described as between 5ft 7in and 6ft tall, medium build, with a moustache.
He was wearing a dark blue baseball cap with a white motif and a blue zip up jacket.