Prime Minister Malcolm Turnbull has joined Islamic leaders in condemning a firebombing and anti-Islam graffiti attack outside a mosque and school in Perth's south-east.

Police have confirmed accelerant was used to set the four-wheel drive alight outside the Thornlie Mosque and Australian Islamic College on Tonbridge Way just after 8:00pm on Tuesday.

The car was gutted, while four other vehicles were damaged by heat.

Accelerant was used to set the four-wheel drive on fire, police have confirmed. ( Supplied: Facebook )

An offensive anti-Islam message was also painted on a nearby wall but has since been removed.

Three men were seen fleeing the area after the attack.

Police have released CCTV vision of the men wearing hooded jumpers, who were last seen running through an alley onto Spencer Road.

The police dog squad tracked a scent from the college to Hughenden Drive, where a vehicle had been parked.

A mosque Imam said hundreds of worshippers were praying inside at the time of the suspected petrol bomb attack, however no-one was injured.

"The Perth community was visited this evening by hate," Yahya Adel Ibrahim said on Facebook.

Police have released CCTV vision of three men seen running from the Thornlie Islamic College. ( Supplied: WA Police )

"Thankfully our community won't start hating and playing blame games and singling out groups of people in our society.

"This, undoubtedly is a criminal act of hate, but it is the act of a person or group not the greater whole.

"Despite what just transpired, everyone stayed to finish their prayers refusing to give into the terror that had just occurred."

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Prime Minister Malcolm Turnbull also denounced the attack.

"[Australia is] founded on a fundamental, a foundation of mutual respect. It's the golden rule ... I deplore and I cannot condemn strongly enough any attacks of that kind," he told Macquarie Radio.

Speaking on 720 ABC Perth, Mr Ibrahim said the shock was heightened by the fact the attack happened during the month of Ramadan.

"There's something not right there within the handful of people who seek to target Muslims with such hate," he said.

Mr Ibrahim said the same kind of graffiti had appeared at other mosques in Perth.

'We get a lot of hatred', parent says

Parents at the school expressed concern for their children, but said the attack was bound to happen.

"We get a lot of hatred, just racism really," mother Zahra Alasadi said.

"[Last night was] one of the holiest days of the month of Ramadan ... people park out here for the mosque, it could be that they're trying to target [Muslims].

Mother Zahra Alasadi said the school had been graffitied before. ( ABC News: Charlotte Hamlyn )

"But this side is the school side, the other side is the mosque side. I don't know what kind of statement they want to make."

Witnesses said they heard an explosion on Tuesday night and went to investigate.



"We stopped and looked, and about 10, 15 seconds later we had seen three guys run across the road. They ended up running through a laneway," local resident John said.

"Straight after we had seen these guys run, we had seen a big flame coming from the back of the house and it looked like a big explosion.... [it] looked like a house was on fire.

"There was a white four-wheel drive on fire and we just hoped there wasn't anyone in there, which there wasn't, thank goodness."

School shocked but heartened by support

Australian Islamic College executive principal Abdullah Khan told 720 ABC Perth he was shocked and disappointed by the attack, but was reassured by the support they had received.

"I had so many calls from the politicians, the state police department, from other community members last night and this morning," he said.

The anti-Islam graffiti has been removed from the wall. ( ABC: Kimberley Howie )

"I had been on the phone almost throughout, and they have been sending messages of support and condemning this attack.

"In fact that is very heartening and it gives us the confidence that the perpetrator is not representative of peace-loving WA mainstream society."

Mr Khan said there had been several previous incidents of graffiti at the college, but said the school would operate as normal on Tuesday.

"We have given them instructions that it is business as usual and children should come to school as they do every single day," he said.

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"In fact the people who were praying last night, they came out obviously when they heard this but after some time when they saw that emergency services and police were there, they went back into the mosque and they continued their prayer.

"That's the message that we want to send to those people that we will not become part of supporting their agenda."

Mr Ibrahim said he had also received offers of help and support and believed the "hate-infused atrocity" would bring people together rather than separating them.

"Australia's built on fellowship and mateship and giving people a fair go and acceptance and love ... we're not going to let that change on account of a handful of criminals," he said.

Second incident in a week

Vandals also scrawled graffiti on a mosque in Southern River on Saturday night and left a pig's head near the main entrance.

Police said they did not think the incidents were linked at this stage.

They said the driver of a blue and silver two-toned dual cab four-wheel drive may be able to assist with their investigation of the Southern River incident.

Police have released CCTV vision of both incidents asked anyone with any information about either of the incidents to contact Crime Stoppers.