A mosque in northern France was attacked by unidentified assailants who left two bloody pigs' heads in the Muslim house of worship, mosque officials said Monday.

The heads were found in the Grand Mosque in the city of Compiegne in Oise, where restoration work is being done, the Turkish-Islamic Union for Religious Affairs (DITIB) in Compiegne said in a statement Monday.

Condemning the incident, the mosque management filed a complaint.

The French Council of the Muslim Faith also denounced the incident and expressed solidarity with the mosque management and the community.

The development comes amid rising anti-Islam rhetoric in France following controversial statements by President Emmanuel Macron.

Claiming Islam is a "religion in crisis," he defended blasphemous cartoons of the Prophet Muhammad, leading to international condemnations, protests and calls to boycott French-made products.