French police are investigating how a group of thieves weilding assault rifles held up an armoured car in broad daylight and got away with more than a million euros in cash.

Adding to the embarrassment of the authorities was the fact that the pictures were filmed as the incident took place on Monday in Marseille and ran prominently on news bulletins.

The pictures show the masked robbers with military-type rifles and assault weapons calmly robbing the truck of its contents.

French media said the thieves had got into the armoured truck by blowing open its rear doors with explosives before carting off the cash.

A passing police car which arrived at the scene towards the end of the robbery was fired on repeatedly with automatic weapons before the criminals fled.