French authorities have arrested six people suspected of involvement in enabling radicalised Muslims to go to Syria, a source with knowledge of the matter said on Tuesday.

Five were arrested in Bordeaux while one was arrested in the Paris area, in an operation led by the Paris anti-terrorist prosecutor's body. All six are being held in custody.

Security concerns have been at the forefront of European politics after a May 22 bombing in Manchester, England, which killed 22 people at a pop concert by U.S singer Ariana Grande.