Two young Melbourne men suspected of having religious extremist motivations are facing terrorism charges over a fire and assault.
The 19-year-old and 20-year-old Epping men were arrested along with a 16-year-old Pascoe Vale boy in separate joint counter-terrorism raids in Melbourne's north on Wednesday.
The 19-year-old will appear before Melbourne Magistrates' Court on Thursday charged with an attempted terrorist act, intentionally causing injury, an act in preparation of a terrorist act and membership of a prescribed terrorist organisation (ISIS).
The 20-year-old is also due to appear before Melbourne Magistrates' Court on Thursday charged with one count of an attempted terrorist act.
The 16-year-old boy was released without charge.
The trio came to the attention of police after a fire in bushland about 30 minutes from Epping on 18 February and an assault in a public place in metropolitan Melbourne on 10 March.
Investigators believe the incidents may have been motivated by Islamic "religious extremism".
Assistant Commissioner Scott Lee of the Australian Federal Police's counter-terrorism and special investigations unit said the nature of fire, in particular, 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 told reporters on Wednesday.
"There are certain aspects to the lighting of the fire that leads us to suspect it was a terrorism motivation."
With all three suspects aged 20 or under, Mr Lee said counter-terrorism teams across the globe were encountering a "younger and younger" demographic, with the COVID-19 pandemic pushing more kids online and exacerbating the problem.