Armed assailants killed two French prison officers and seriously wounded three others in an attack on a convoy in Normandy on Tuesday and an inmate escaped, officials said. A search was underway.

The convoy was transporting prisoner Mohamed Amra to Évreux jail after a court hearing in Rouen when it was ambushed on the A154 freeway, which has been closed.

"All means are being used to find these criminals. On my instructions, several hundred police officers and gendarmes were mobilized," Interior Minister Gerald Darmanin posted on social platform X.

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French President Emmanuel Macron in a post on X called the attack "a shock for all of us."

Authorities worked to secure the area in northwestern France and apprehend the assailants. It was not clear how many were involved.

Amra was detained at the Val de Reuil prison center near Rouen following his recent sentencing for burglary. He was also under investigation for a kidnapping and homicide case in Marseille, according to public prosecutor Laure Beccuau.

French media reported that Amra was nicknamed "La Mouche" (The Fly).

Beccuau announced an investigation into the attack, considered a case of organized crime and murder, and said two of the wounded officers were in critical condition.

The investigation will also address organized escape attempts, possession of military-grade weapons and conspiracy to commit a crime.