PARIS: A mosque in the French city of Limoges has been desecrated by having human excrement smeared on its doors, Interior Minister Manuel Valls said Wednesday in a statement condemning the incident.

The attack occurred overnight following reports of mob violence in Egypt and Libya involving Islamists angered by a U.S.-made film said to insult the Prophet Mohammed.

There was no immediate indication however that the desecration was a reaction to or linked to the unrest over the film.

"This attack is a grave assault on the dignity of Muslims and is shocking for every citizen who upholds the values of respect and tolerance," Valls said in his statement.

The incident in Limoges, in the centre of France, came a month after two pigs heads were deposited at the entrance of a mosque in Montauban in the south of the country.

France is home to at least four million Muslims and leaders of the largest Islamic community in Europe say incidents of Islamaphobia are on the rise against a background of confrontation with the authorities.

Many Muslims have been angered by legislation banning women from wearing full veils and this year's elections were marked by debate over the use of halal methods of animal slaughter.