Police said Tuesday that vandals have damaged or destroyed dozens of stone markers over the graves of Muslims buried in the central cemetery in the southern city of Graz.

Authorities in Graz, about 200 kilometers (120 miles) south of Vienna, said about 60 gravestones were overturned and many were broken.

It was unclear when the attack occurred.

Officials with a local human rights commission said they could not rule out the possibility that extreme-right groups active in the city may have been behind the vandalism.

Tensions have risen in Graz since a local politician from the right-wing Freedom Party made a disparaging comment about the Prophet Muhammad.