Anti-weapons protesters who vandalised a defence manufacturer and set nearby vehicles alight could face life imprisonment after police said the incident was being investigated as an act of terrorism by “far-left extremists”.

The Australian federal police, their Victorian counterparts and spy agency Asio are examining whether the incident at Melbourne-based Lovitt Technologies on 5 July 2025 was potentially perpetrated by “far-left extremists, motivated by anarchist and revolutionary ideologies”, a joint statement said.

Related: High-ranking NSW police officer apologises for failing to alert Jewish groups to neo-Nazi Sydney protest

If convicted, they could face life imprisonment, AFP detective superintendent Anthony Hall warned.

“We clearly have some information about these alleged offenders and are focused on identifying who they are,” he said.

“The AFP, together with our partners, will not tolerate acts of terror motivated by extremist ideologies aiming to cause fear and anguish in our community.

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“At any time, we could be knocking on the door of the accused group. We know this is making some in the group anxious – and it should, because we are determined to bring them before the courts.”

Wearing black hoodies, backpacks and gloves, members of the group claimed responsibility for the attack in a video posted online.

Their video advises viewers on how to create an incendiary device, similar to the one suspected of creating a fire that damaged three vehicles at Lovitt Technologies, and voices their opposition to the government.

In a video seen by Guardian Australia, a person who claims to represent the “anonymous cell” responsible outlines support for Palestine and claims Lovitt Technologies was targeted because it supported the global F-35 joint strike fighter program, whose jets are used by the Israeli military.

“This was not an accident nor thoughtless vandalism,” the person, whose voice was digitally altered, said.

“If you continue making weapons components of any kind, there will be consequences.”

Lovitt Technologies supplies parts to the joint strike fighter program, whose global supply chain has been subject to fierce political debate in Australia and a major legal challenge in the UK.

But all companies and their employees had a right to go about their business safely, Victoria police’s Acting Supt Anthony Wheatfill said.

“That anyone would use such violent and dangerous methods to express a political or social viewpoint is unacceptable,” he said.

After the incident, the alleged offenders left using a back fence and rode ebikes south-west along Plenty River.

Community members with knowledge of the offenders or dashcam footage have been urged to come forward.

Melbourne anti-weapons protest being investigated as terrorist act by ‘far-left extremists’