The arson squad is investigating a suspicious fire which damaged a mosque in Mirrabooka, which started just hours after Perth's Islamic community celebrated an important religious festival.
Fire crews were called to the scene about 12.20am.
The fire damaged chairs and a tree and smoke damage inside the mosque.
Police were still at the scene at 6.50am.
On Saturday night, the Islamic community in Perth's northern suburbs celebrated Eid, a festival marking the end of Ramadan.
Hundreds of people commemorated the festival at Herb Graham Recreation Centre in Mirrabooka.
A police spokesman did not comment and did not say whether the fire is believed to be deliberately lit.
Arson Squad Detectives appealed for anyone with information to call Crime Stoppers on 1800 333 000 or make a report online at crimestopperswa.com.au.