Paris, France: France's defence ministry said Monday it could not confirm whether French jihadists had been killed in air strikes on a training camp for Islamic State militants in Syria.

A source in the delegation of Prime Minister Manuel Valls, currently visiting Jordan, earlier said the strikes had probably killed French jihadists.

"Overnight Thursday to Friday, France bombed a jihadist training camp belonging to Daesh (IS). We know that this camp aimed to train fighters to come attack Europe and France," the ministry told AFP.

"French citizens or French speakers may have been among them. At this stage, we cannot confirm with accuracy anything related to this bombing."

On his trip to the Middle East, which has also taken him to Egypt, Valls said France would strike anyone planning attacks on its soil, regardless of nationality.

"Anyone who joins these training camps, anyone who joins Daesh should know that they can now be attacked," the French premier said on Sunday.

French authorities have stepped up efforts to fight radicalisation since a series of jihadist attacks by gunmen left 17 dead in January in Paris.

France has been named as a priority target by IS militants and several other attacks have been foiled, amid fears that battle-hardened jihadists could return from Iraq or Syria to launch attacks on home soil.