Three prison officers have been shot dead and three others seriously wounded when a gang attacked a convoy in northern France today so as to free a convicted drug dealer.

The bloodbath unfolded on Tuesday at a motorway toll booth near the town of Val-de-Reuil, Normandy, and led to Mohamed A. escaping. The ambush took place near a toll booth on the A154 motorway, which is now closed in both directions.

The prisoner and gang members initially escaped in two cars – an Audi A5 and a BMW 5 series. The BBC reports that the prisoner is still on the run with the attackers.

A local police souce said: "The ambush happened at the Incarville toll booth on the A154 road. Kalashnikovs are thought to be have been used.

"Three prison officers are thought to be dead, and three others are seriously wounded.

Alexandre Rassaërt, president of the Eure Departmental Council, which covers Vale-de-Reuil, said: "I was frozen with horror when I learned of the real carnage that took place at the Incarville tollbooth.

"I sincerely hope that the gang of killers who carried out this bloody attack will be quickly arrested.

"All my thoughts go to the families of the service agents. penitentiary who escorted the detainees and who were killed or seriously injured during this attack which gave them no chance.

"I also think of all the prison administration guards who, every day, guard prisoners at the risk of their lives.

France’s Justice Minister Eric Dupond-Moretti said: "All my thoughts are with the victims, their families and their colleagues."