The thefts at the Miramas site, which is operated by a combination of military services west of Marseille, appeared to have occurred overnight from Sunday to Monday. The break-in comes as France has strengthened its security measures after two deadly attacks by extremists this year.
Marseille prosecutor Brice Robin said an investigation has started on charges of "theft with break-in carried out by a criminal group" and "fraudulent entry into a military compound."
