A Twitter account associated with IS has tweeted a photograph of Mr Bilardi with the caption: "For today's Martyrs". A television screenshot of one of the cars reportedly involved in a suicide bombing and (inset) a youth who bears a strong resemblance to Melbourne teen Jake Bilardi. Fairfax Media has not been able to independently verify the claims. A spokesperson for the Department of Foreign Affairs and Trade (DFAT) said the Government had been unable to confirm the reports of Mr Bilardi's involvement in the car bombings. In a blog believed to have been written by Mr Bilardi, and entitled "From Melbourne to Ramadi: My Journey", the author writes an online manifesto, describing his radicalisation process, his "Plan B" to attack public places in Melbourne and, ultimately, his decision to volunteer for martyrdom in Iraq. The blog, discovered after his apparent death, lays out how he became disillusioned with Western society and fascinated by Islam.

It describes how he had started collecting explosives to launch an attack in Melbourne, before he eventually decided to travel to the Middle East. Unconfirmed reports say Jake Bilardi (centre) took part in a suicide bombing. Credit:Twitter The ABC is reporting that Bilardi's family discovered a number of improvised explosive devices at their home following his departure for the Middle East. They reportedly alerted authorities, who began tracking Mr Bilardi's movements overseas. Prime Minister Tony Abbott said he had been told of unconfirmed reports of Mr Bilardi's involvement in a suicide bombing. "This is a horrific situation, an absolutely horrific situation, and it shows the lure ... of this death cult to impressionable youngsters," Mr Abbott said.

"It's very, very important that we do everything we can to try to safeguard our young people against the lure of this shocking, alien and extreme ideology." Iraqi officials have confirmed a series of coordinated car bomb attacks were launched on Ramadi, about 90 kilometres west of Baghdad, overnight. Reuters reported that 13 suicide car bombs were detonated, while the New York Times reported as many as 21 were carried out in what was described as one of the militant group's fiercest assaults in months. Hikmat Suleiman, the political adviser to the governor of Anbar, told the New York Times that Iraqi forces in Ramadi were able to keep casualties in the car bombings to a minimum by attacking and thwarting the vehicles as they approached the city. The Iraqi forces blew up most of the vehicles before they reached their apparent targets, he said.

A medical source said five people were killed in the attacks, but the real figure could be significantly higher. One of the car bombs exploded near a bridge in the west of the city and damaged part of the bridge, a police source said. Mr Bilardi is believed to have become radicalised online following the death of his mother from cancer. He converted to Islam at the age of 16 and started visiting local mosques in the northern suburbs of Melbourne. He also began using the names Abdur Raheem or Abu Abdullah. The gifted maths student attended Craigieburn Secondary College, before switching to Rosehill Secondary College in Essendon at the beginning of 2014.

However, he dropped out of high school last year and bought a one-way ticket to Turkey, before heading to Iraq and Syria to fight for IS. In the lead-up to his religious conversion, Mr Bilardi was regularly reading news from the Arab world and making comments on the "evil" of the United States, Israel and Australia. Mr Bilardi's best friend claimed that Mr Bilardi had self-radicalised on the internet using foreign media sources and a deep belief that significant wrongs had been done against Islam. Victorian Premier Daniel Andrews said he was yet to be briefed on the case, but he condemned the reported suicide bombing. "This is just evil. It is unconfirmed, but if it is true it is desperately, desperately sad and tragic," Mr Andrews told 3AW. "It really shows that none of us are immune from these events, even though they are occurring on the other side of the world."

Following reports of the suicide bombing, BBC journalist Secunder Kermani said that he had interviewed the young Australian in December, when the teenager told him he was "chasing death". The DFAT spokesperson said the Federal Government's capacity to confirm reports of deaths in Syria or Iraq was extremely limited. "Due to the extremely dangerous security situation, consular assistance is no longer available within Syria," the spokesperson said.

"Australians who become involved in overseas conflicts are putting their own lives in mortal danger. Any Australians fighting with non-state militia in Syria or Iraq should end their involvement in the conflict now and leave the conflict zone. Australians are strongly advised not to travel to Syria or Iraq; any Australians in either country should leave immediately." - with Marissa Calligeros, Latika Bourke