Paris ? Vandals scrawled swastikas and other Nazi references on the walls of the Grand Mosque of Paris, the most prominent Muslim religious site in France, religious leaders said Monday.

Authorities also investigated a possible arson attack on a memorial for Jews deported to Auschwitz in World War II, amid an increase in anti-Muslim and anti-Jewish vandalism.

The mosque vandals scrawled about a dozen swastikas, other Nazi references and “Get Out” on the white walls around the imposing, decades-old house of worship in southeastern Paris.