A Melbourne man has been accused of trying to carry out a religiously motivated act of terror, with police warning the COVID-19 pandemic has exacerbated online youth radicalisation.
The 19-year-old Epping man was among three people arrested as part of a joint counter-terrorism operation in Melbourne's north on Wednesday morning.
A 20-year-old man from Epping and 16-year-old Glenroy boy were also arrested in the separate raids after investigators became concerned about a fire and an assault.
Police say they suspect the incidents - involving a fire in bushland about 30 minutes from Epping on 18 February and assault in a public place in metropolitan Melbourne on 10 March - may have been motivated by "religious extremism".
"It is Islamic," Assistant Commissioner Michael Hermans told reporters.
"But let me make it very clear that we target the crime, not the ideology. It makes no difference to us."
Fellow Assistant Commissioner Scott Lee, from the Australian Federal Police's counter-terrorism and special investigations unit, said the nature of fire had stoked their suspicions.
"There is an ideology, and a violent extremist ideology, that has caused us concern, and it's as a result of that ideology that we're looking at these incidents being connected to a terrorism motivation," he said.
"There are certain aspects to the lighting of the fire that leads us to suspect it was a terrorism motivation."
Mr Hermans said police took action on Wednesday after observing an increasing "risk profile" among the trio.
Two of the males are from the same family. Neither has been charged, although Mr Lee flagged terrorism-related offences could be laid later on Wednesday.
Police allege the 19 year old attempted to engage in a terrorist act, which can carry a potential sentence of life in prison.
The teenage boy has been released pending further inquiries.
No further arrests are expected.
"The three individuals that we've taken action on today, we're comfortable that has contained the risk," Mr Lee said.
With all three males aged 20 or under, Mr Lee conceded counter-terrorism teams across the globe were dealing with a "younger and younger" demographic.
There is a range of factors behind the "phenomenon", but the magnification of the online environment should not be underestimated, he said.
"That's certainly what we've seen throughout the COVID period as people have come out into the physical world (after being) in isolation and driven into the online environment," Mr Lee added.
"That's really exacerbated some of the radicalisation that we've seen. Not only around the country but also globally in terms of counter-terrorism environment."
