French police have launched a nationwide manhunt after two correctional officers were shot dead in an assault on a prison van on Tuesday morning. The attackers opened fire on the van with heavy weapons and freed a gang leader suspected of murder.

The attack took place at a toll booth on the A154 motorway between Rouen and Evreux in Normandy. Arriving in two vehicles, the perpetrators blocked the prison convoy before opening fire on the officers with “heavy weaponry,” French Justice Minister Eric Dupond-Moretti told reporters.

Two guards were killed and three seriously injured, Dupond-Moretti stated.

Video footage shot by a passing bus passenger shows two hooded men armed with rifles moving toward the van, which had been rammed by a black SUV. Alternate footage captured by the toll booth’s security cameras shows four men surrounding the van, executing the officers, and detonating what appeared to be an explosive device before fleeing the scene.