AJACCIO, France (Reuters) - A Muslim prayer hall was seriously damaged by fire overnight in the capital of the French island of Corsica, local authorities said, four months after a separate Muslim prayer hall there was ransacked.

No one was injured in the fire in Ajaccio, which police are investigating as criminal after finding two separate sources of fire inside the hall.

“This is unacceptable,” Ajaccio mayor Laurent Marcangeli told iTELE newschannel. “Those sites are not sufficiently protected.”

In late December, the island was rocked by days of racial tension after firemen in Ajaccio were attacked on a housing estate with a large immigrant population and a Muslim prayer hall was attacked in anti-immigrant protests that followed.