He stressed in an interview with the French news channel BFM TV: “There is a security risk in that there are between 10,000 and 15,000 jihadists currently holed up in that zone.
“These people are for the most part loyal to al-Qaida and pose tomorrow’s biggest security risk.”
Russian-backed Syrian regime forces have been massing on the borders of Idlib for weeks, sparking fears its three million residents will be cut off from humanitarian and medical aid.
Mr Le Drian added that “around a dozen” of Idlib’s jihadists were French nationals who could disperse across Syria and eventually France if the Syrian-Russian attack goes ahead as planned.
It appears that there is some sort of psychological preparation for a chemical attack by Russian groups
Jean-Yves Le Drian
France has been at the centre of terrorist attacks since 2015, and authorities are on high alert for “returnees,” foreign fighters returning home from Iraq and Syria following the defeat of ISIS in its former strongholds.
France’s diplomacy chief also expressed concern Damascus might once again resort to the use of chemical weapons to wipe out the rebels, adding that a chemical attack remained a “red line” for France.
Mr Le Drian added: “It appears that there is some sort of psychological preparation for a chemical attack by Russian groups, who would like to blame [the attack] on terrorists.”
His comments come amid claims Moscow had accused Syrian rebels of staging an attack as a pretext for Western intervention.
Mr Le Drian added: “If Russia takes the risk of backtracking on its commitment to help stabilise Idlib province, it also takes the risk of finding itself completely alone to deal with the potentially devastating consequences of an offensive.”
Bashar al-Assad’s regime has been repeatedly accused of using chemical weapons during the seven-year war, and western governments, including those of France, Britain and the United States, have promised serious reprisals if Mr Assad orders another chemical attack to recapture Idlib.
The northern province is the rebels’ sole remaining major stronghold and a government offensive could be the civil war’s last decisive battle.