French authorities revealed on Tuesday that they had arrested a man with ties to Islamic State (ISIS) in Syria, who was planning an attack on a major naval base.

The 25-year-old man had been monitored ever since twice trying unsuccessfully to travel to Syria last year, and was detained last month before being charged on November 2, reports AFP.

A statement by the French Interior Ministry clarified the man was being watched “because of his radicalization and public support for jihadist ideology” and that he had “attempted to acquire material to carry out a violent attack on Navy personnel in Toulon.”

Unaware that he was being monitored by the authorities, the man had a package delivered which contained a combat knife and a mask.

He admitted under investigation to being in contact with a French national currently fighting for ISIS in Syria, and that the contact had urged him to launch an attack in France.

The man admitted to planning an attack against Navy personnel at the military base on the Mediterranean Sea in Toulon, where no less than 70% of the French fleet is housed.

A full 20,000 military and civilian personnel are present at the base.

One source indicated that the French ISIS fighter who the man was in contact with had been arrested in France back in 2012 for making threats against Charlie Hebdo, the magazine whose headquarters in Paris were targeted in an Islamic terror attack in January murdering 12 victims.

Just days after that attack, an Islamic terrorist murdered four Jews at a Kosher supermarket in Paris.

No less than 500 French nationals are thought to be fighting for ISIS in both Syria and Iraq. Some 250 have returned from fighting for ISIS, posing a very real threat of local attacks, and 750 Frenchmen have said they want to go to the region to fight for ISIS.