A mouse triggered panic and a crush in a Casablanca mosque has left more than 81 injured, mostly women, the Moroccan news agency MAP reported.

The incident occurred in the city's Hassan II mosque, which was packed during evening prayers Tuesday, the holiest night of the Muslim fasting month of Ramadan, MAP said.

"Eighty-one people, mostly women, suffered light injuries and fractures while some of them fainted," it said.

The panic broke out after a woman raised the alarm over the mouse, sparking a sudden exodus of screaming worshippers.

Among those needing treatment was a pregnant woman who suffered a double fracture in the leg and has been kept under surveillance in hospital.