A Darwin teenager has been charged with numerous offences after police executed a search warrant and allege he was “collecting documents likely to facilitate [a] terrorist act, as well as schematics for 3-D printed guns”.

A investigation by the NT Joint Counter Terrorism Team (JCTT) was launched earlier this month involving the AFP, NT Police and ASIO after a Crime Stoppers tip-off about the alleged online posting of “violent extremist material”.

The JCTT allege the teen, whose age was not disclosed, was the operator of several social media channels in which he accessed, discussed and reposted that material.

Police raided a premises in Darwin on Wednesday, seizing documents and multiple electronic devices which it is alleged contained violent extremist material and “referenced violent attacks”.

“During an initial examination of the devices, investigators also identified alleged instructional schematics for the manufacture of 3-D printed firearms and other instructional documents and manuals investigators will allege are likely to facilitate a terrorist act,” an AFP statement said.

The teen was scheduled to appear in a children’s court today to answer to three charges, including one count of making documents likely to facilitate terrorist acts; one count of possessing violent extremist material obtained using a carriage service; and one count of possessing or controlling firearms and explosives manufacture material obtained or accessed using a carriage service.

The maximum penalty for the first offences is 10 years’ jail, while the other two charges carry a maximum of five years each.

AFP Counter Terrorism Commander Paula Hudson said authorities were becoming concerned about young people becoming radicalised through online material.

“The speed and scale of radicalisation is becoming one of our most significant challenges, especially when it comes to young people,” she said.

“We need a whole-of-society effort to provide the protective factors that keep our youth safe from radicalisation and manipulation – and find ways to ensure they can be resistant to these threats.”

The AFP encouraged parents and others to recognise changes in a young person’s behaviour and said some of the signs a person may be susceptible to radicalisation include distancing themselves from their usual friends and family; an increase in extremist comments or rhetoric; using hateful or emotionally charged language; developing a fixation on conspiracy theories or “contentious social issues”; displaying extreme reactions to news or politics; and spending more time in “fringe forums on the internet”.

“If you suspect someone is being radicalised online or in person, call the National Security Hotline on 1800 123 400,” the AFP said.

“For anonymous reporting, visit the Crime Stoppers website or call 1800 333 000.

“Information and support are also available at the Step Together website, which is a helpline and digital support service for people seeking advice on how to support loved ones and protect them from negative violent extremist interest.”