Western Australia police were investigating a racist firebomb attack at a mosque in state capital Perth while hundreds were praying on Tuesday evening, officials said on Wednesday.
No one was injured in the attack, during which a parked car burst into flames outside the mosque, Xinhua news agency reported.
It was believed petrol or a fire accelerant was used in the blaze.
Anti-Islamic graffiti was also spotted on a wall near the Australian Islamic College, close to the mosque.
Perth Now daily reported Australian Islamic College Yahya Adel Ibrahim wrote on Facebook that worshippers finished their prayers despite the chaos outside the mosque.
Ibrahim said the Perth community had been “visited by hate” but “wouldn’t start playing blame games and singling out groups of people in our society.”
“Despite what just transpired, everyone stayed to finish their prayers, refusing to give in to the terror that had just occurred,” he added.