Scammers in $2m road heist

German authorities say thieves posing as police officers have made off with €1 million ($2 million) in gold and jewellery.

The German news agency DAPD reports four thieves in a dark BMW with a police light and a red VW van with Nuremberg plates pulled the transport truck over near the southern city of Ludwigsburg.

The thieves wore black pants and jackets with "police" on them and told the driver and his passenger they were customs officials confiscating the shipment.

The men didn't know they were being scammed until the thieves tied them up and left them on the side of the road.

Police say they are still searching for the suspects and the vehicles.