They are reported to have got away with £50,000 in cash, but West Yorkshire Police would not confirm the figure.
The gang of five – all Asian men including two with beards – are said to have taken “a large amount of cash” from two victims in Buck Street, Bradford, at 2.30pm.
They escaped in a black Honda Civic car towards Leeds Road. One of the men, who brandished what is believed to have been a handgun, assaulted one of the victims.
Detective Sergeant Rob Worley urged members of the public not to approach the suspects but call Police on 101.