'They have nothing to lose. We do': Australia struggles with extremist threat

"He was a groomsman at my sister's wedding."

For a small number of Muslim Australians living here, theirs is a life of alienation, he says. The university student, who is from Melbourne, tells CNN that despite what they have in common, many young Muslims are made to feel like strangers in their own land.

"I do believe it's because of a lack of belonging here in Australia," he says from his university campus. "When anyone travels overseas often there we're known as Australian. Here in Australia we're known as foreigners."

Around 220 Australians have traveled to Syria and Iraq, where around half are believed to be currently fighting or engaged with terrorist groups, according to an Australian Security Intelligence Organization (ASIO) spokesperson.

Counter-terrorism experts like Greg Barton, chair of Global Islamic Politics at Deakin University, believe the figures could be even higher. He estimates as many as 260 Australians could have traveled to the region, most of whom have taken up arms with ISIS.

While the Muslim population in Australia is relatively small, a study last year from the National Bureau of Economic Research suggested the country ranks highly in comparison to other English-speaking nations when it comes to the number of ISIS foreign fighters per Muslim population.

Hass Dellal, executive director of the Australian Multicultural Foundation, says communities need to provide a much stronger counter-narrative around the allure of groups like ISIS.

His foundation has received funding from the Australian government to run workshops that teach families, police and community workers to look for the warning signs of radicalization.

"The messaging that's coming out is nothing but propaganda, and it's about luring them into a false sense of security," Dellal says, listing some of the messages of inclusion he says ISIS tells disaffected Australians.

"'We'll make you feel better. We'll make you feel important. We'll give you a family. We'll give you a sense of belonging. We'll give you some worth. Come and fight for a cause.'"

While the prospect of radicalized Australians traveling overseas is worrisome, there is a more local, pressing problem.

There have been five terror attacks in Australia since September 2014, when the national terrorism threat level was raised, and 13 "major (counterterrorism) disruptions" -- foiled plots -- according to an Australian Security Intelligence Organization (ASIO) spokesperson.

The most high-profile attack to date was the December 2014 siege on a Sydney cafe where a self-styled Muslim cleric took 17 people hostage. Two hostages and the gunman died.

The latest threat was exposed last week, when two men living in Sydney were charged with terror-related offenses. They have not entered a plea.

Federal police allege they were involved in a shocking plot, the "most sophisticated" ever conceived on Australian soil, which centered around an attempt to bomb a passenger plane, though the plan was aborted.

They were also allegedly planning to launch a poison gas attack in a crowded public place.

If the perpetrators hadn't been thwarted, the attacks would have been "catastrophic," Australian Federal Police Deputy Commissioner Michael Phelan said.

The men had been in direct contact with a senior ISIS commander who sent bomb components to them in the Sydney suburbs, police allege.

With ISIS suffering defeats in Iraq and Syria, there's concern it will pull out all stops to demonstrate it remains a potent force.

Those at home -- with connections abroad -- are the ones experts say need to be watched, says Barton.

"In some cases we've got ticking time bombs. People who are broken, confused and if approached and groomed by those who want to use them, could once again become dangerous."

There are around 600,000 Muslims in Australia, the vast majority of whom disavow ISIS' brutality.

One high-profile Muslim community leader told CNN that news that the plot was disrupted was met with relief.

"Relief because they were caught before the act, and relief for those innocent people," said Jamal Rifi, a Australian Lebanese Muslim GP, who has run his own surgery in Sydney for 27 years.

Relief too, he noted, "because just imagine the sort of backlash that would happen to the Muslim community if something like this takes place."

Many Muslim groups, particularly conservative Salafi communities in Sydney and Melbourne, say they feel under siege by the rise of conservative politics in Australia, says Clarke Jones, a criminologist at Australian National University who works in de-radicalization and counter-terrorism.

"You have people who feel racism, particularly young people who don't have those critical thinking skills. It's a complex issue, so the solutions are very complex too."

The university student who saw two of his friends travel to ISIS-held territory says the government isn't doing enough to deter them.

"It will be a lot more worse than it is now because we are not doing enough to stop it and if (ISIS) have any means to contact people they will do it. They have nothing to lose. We do."

The government has poured tens of millions of dollars into de-radicalization programs across the country that work with communities and families to identify early warning signs.

And while prevention is hard to measure, organizers are confident they're seeing results, particularly from efforts to work with Muslim communities and their leaders to nip radicalization in the bud.

"There aren't many mothers who are going to dial a hotline and dob in a son even if they feel something is wrong," says Dellal.

"But they may do something at the grassroots level, if they're connected to people they can trust and confide in."