Around 200 detonators as well as plastic explosives and grenades were stolen from a military site in France Sunday night, and French authorities have started investigating. The site, in the southern part of the country, houses weaponries used by French troops in Mali and Afghanistan. 

A combination of military services west of Marseilles operates the Miramas site where the theft took place. According to Marseilles prosecutor Brice Robin, an investigation related to “fraudulent entry into a military compound” and “theft with break-in carried out by a criminal group” has started.

The theft at the Miramas site, which is operated by a combination of military services west of Marseille, appeared to have taken place overnight from Sunday to Monday. The break-in came with France on its highest level of alert for terrorism following deadly attacks in January and June. The military site has guards patrolling with sniffer dogs.

According to an official with the gendarmerie police force, the thief might have cut through a fence to get inside the high-security site. Miramas Mayor Frederic Vigouroux acknowledged that it had been the first theft there.

Vigouroux said even though he was not aware of what exactly had been stolen, some “dangerous munitions” were involved. “It wasn’t cotton candy that was stolen,” The Guardian quoted him, “Everything is inherently dangerous.” According to a French military spokesman, the stolen explosives are quite easy to use.

According to Sky News, France has been on the highest terrorism alert since the Charlie Hebdo attacks in January. In June, ISIS militants were allegedly involved in the beheading of a man near Lyon.

French defense minister Jean-Yves Le Drian ordered a  review of the security of all military weapons stocks in the country, which would be conducted by a new office in charge of protecting those sites. He also instructed to propose “corrective measures” within the next couple of weeks. The investigation is going to find out who was responsible for the break-in and how it was organized.