Staff and customers at a travel agency were threatened by a man who made off with a significant amount of money, including foreign currency.
The man entered Thomson travel agents at Riverside Quay in Haverfordwest, Pembrokeshire, on Friday, and demanded staff hand over cash.
Dyfed-Powys Police say no-one was injured in the raid.
A Thomson spokesperson said the company was assisting the police with their enquiries, adding: “Our retail incident support manager has already been on hand to offer assistance to all staff involved and the company will continue to support them in every way possible.
“As this incident is subject to a police investigation we are unable to comment further.”