Police have arrested a 36-year-old man after a fire broke out at a mosque in Cardiff on Tuesday morning.
The fire began on the second floor
Officers and fire crews were called to the Madina mosque in Cathays, just before 0830 GMT when a fire on the second floor spread to the roof.
South Wales Fire Service said about a quarter of the building was lost to the fire, but they were able to save a number of meeting rooms.
The mosque remains closed while forensic examinations are carried out.
Police said they would be holding a meeting later with mosque leaders to update them on the investigation.
The road with the mosque was cordoned off.
A command room has also been set up at Cardiff Central police station.
Superintendent Bob Tooby said it appeared there was more than one seat of fire and that was being investigated by both police forensic scientists and the fire service.
South Wales Fire Service sent four pumps and a hydraulic appliance to the scene and relief firefighters were called to help tackle the blaze.
Cardiff council has offered to meet mosque leaders to discuss providing temporary accommodation, if required.