Security staff have been robbed of a five-figure sum of money during a transfer of cash at a bank.
The G4S employees were inside the Santander bank on West Princes Street in Helensburgh, Argyll and Bute, when two men entered and threatened them with weapons at about 12.30am on Wednesday.
The men then ran off with the cash box.
Police said inquiries are at an early stage and have appealed for witnesses.
The suspects are described as being of medium height, medium build and were wearing blue overalls and masks.
Detective Inspector Douglas Wilson described the incident as a “calculated robbery”.
“The employees were placed in a state of fear and alarm as two men entered the premises of the bank, threatened the men with weapons and then made off with the cash box in an unknown direction,” he said.
“A substantial investigation is under way to trace the men responsible. A dedicated team based at Helensburgh police office is currently analysing any available CCTV.
“Officers remain at the scene on West Princes Street and local door-to-door inquiries are currently being progressed.
“At this time we are seeking the assistance of the public to come forward with any information which could help our investigation.”