The building housing French presidential candidate Marine Le Pen's campaign headquarters was hit by an arson attempt on Thursday, firefighters and police said, with only minor damage caused. Firefighters were called in and quickly extinguished the fires.

The anti-globalisation, nationalist Le Pen is neck-and-neck with leftist, establishment-Emmanuel Macron in polls for the first round of the election on April 23.

A police source said the cause of the fire was "not natural and probably criminal", adding that the graffiti slogan "FN vs KLX" was found nearby.

A group contacted AFP to claim the attack.The anonymous caller, also threatend to continue such actions until the election.