Anti-weapons protesters who allegedly 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

A video posted online after the incident by a masked 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.

The video also raised the prospect of further vandalism or targeted action.

“This was not an accident nor thoughtless vandalism,” the person said.

“If you continue making weapons components of any kind there will be consequences … Stop arming Israel or else …”

The alleged perpetrators were being investigated in relation to the offences of engaging in a terrorist act under the federal criminal code and “other acts done in preparation for, or planning, terrorist acts”, the AFP said.

If convicted, they could face life imprisonment, AFP Det Supt 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.”

Multiple legal sources said there had been a series of counter-terror raids in the past six weeks that activists suspect were linked to the investigation.

This included warrants that resulted in the seizure of devices such as mobile phones.

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

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.

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.

While it is rare for Australian authorities to investigate far-left groups for alleged terror offences, Asio warned recently of an increased threat it said was posed by those motivated by the Gaza conflict.

“While nationalist and racist violent extremists make up the significant majority of our investigations into ideologically motivated extremism, events in the Middle East triggered a troubling increase in anarchist and revolutionary extremism, which is also straining cohesion,” Asio director general Mike Burgess said last November.

“Since October 2023, we’ve seen more provocative protests and a notable uptick in intentionally disruptive and damaging tactics by anti-Israel activists, including multiple acts of arson, vandalism and violent protest against defence companies accused of supplying weapon components.

“These groups – for want of a better word – are not as centrally controlled, uniformly motivated or as disciplined as the [far-right] National Socialist Network, but they contain individuals who are increasingly willing to embrace or threaten violence to achieve their goals.”

The UK has also seen several cases of individuals charged with terror offences after damaging businesses with suspected links to the Israeli government, including the so-called “Filton 4”, who were convicted for criminal damage offences linked to a protest at the Elbit Systems factory in Filton, near Bristol.

In Melbourne, terror charges were previously laid in relation to an unrelated 2016 attack involving arson and criminal damage when Islamic State supporters set fire to a Shia mosque. The terror group had encouraged violence against Shias.

In that case, lawyers for the men argued in court that an alternate charge of arson should be available as a verdict to the jury, rather than only the terrorism offence.

The judge denied that request, as did the Victorian court of appeal, which found that the decision was justified given the law specified that a terrorist act was defined as being done with “the intention of advancing a political, religious or ideological cause” and could include an action that “causes serious damage to property.”

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