US police are hunting hackers who tapped into the radio at a fast food drive-through and insulted customers.

The offenders are reportedly tapping into the wireless frequency at the Burger King restaurant in Troy, Michigan, AP news agency reported.

One customer who placed an order was told: "You don't need a couple of Whoppers. You are too fat. Pull ahead."

Another customer who had placed an order for Coca-Cola: "We don't have Coke."

When the customer asked what they had, the hacker said: "We don't have anything. Pull ahead."

Police suspect that calls are being made using a radio transmitter or walkie-talkie near the restaurant.