The Australian government has raised the country’s terrorism threat level from “possible” to “probable” as security officials warn of an increased risk of violence “across all ideological spectrums”.
The prime minister, Anthony Albanese, made the announcement in Canberra on Monday, reversing a change made nearly two years ago.
Intelligence sources said the decision to raise the threat level was not triggered by any single issue or ideology, but noted an overall increase in polarisation in Australia and other western countries.
The sources said social cohesion was under strain and Covid-era grievances were being exacerbated by the Israel-Hamas conflict.
The terror threat level was last changed in November 2022, when it was lowered to “possible”.
“I want to reassure Australians probable does not mean inevitable and it does not mean there is intelligence about an imminent threat or danger,” Albanese said on Monday.
“But the advice that we have received is that more Australians are embracing a more diverse range of extreme ideologies and it is our responsibility to be vigilant.”
The prime minister appealed to fellow political leaders to watch their language and to engage in public debate in “a way that is respectful”.
“When the temperature of the security environment is rising, we must lower the temperature of debate – something I’ve been saying for some time,” he said. “Our words and our actions matter.”
The Greens senator David Shoebridge said it was “deeply irresponsible for prime minister Albanese to use this moment as a platform to air his political grievances and conflate good people concerned with specific actions of his government with far-right conspiracy theorists”.
Australia’s terrorism threat level is rated by security officials on a five-level scale, with “not expected” the lowest rating and “possible” the second-lowest rating.
Monday’s change moves the rating to the mid-level of “probable”. After probable, the more serious levels are “expected” and then “certain”.
The level of “probable” means that security officials believe “there is a greater than 50% chance of an onshore attack or attack planning in the next twelve months”.
The official advisory warns of the potential for “an increase in acts of politically motivated violence, including terrorism, to occur across all ideological spectrums”.
The advisory says the spy agency Asio is “observing the emergence of domestic actors increasingly driven to action by socio-political issues, intersecting with personal grievances”.
“There is an increase in extremism, fuelled by conspiracy theories and anti-authority ideologies,” it states.
“Some actors hold a blend of ideologies, including those that justify acts of violence to influence change.”
The advisory says the “rise of individual grievance narratives and how they are expressed” are affecting society’s “ability to find common ground”.
“Increasingly it is leading to a normalisation of provocative and inflammatory behaviours contrary to community standards and liberal democratic values,” it says.
The advisory warns that any attack in Australia is “likely to be low-cost, using readily available weapons, and simple tactics”.
Asio said such an attack would be most likely to occur in a crowded place in a major city and by a “lone actor” or a small group in a way that was difficult to detect in advance.
The head of Asio, Mike Burgess, said Australians “should be aware but not afraid” – an adaptation of the Howard government-era warning to be “alert but not alarmed”.
Burgess said he was particularly concerned about the rapid radicalisation of young people online.
“Politically motivated violence now joins espionage and foreign interference as our principal security concerns,” he said.
Burgess said he had warned in October that inflamed language about the conflict in the Middle East could inflame tensions in Australia.
“Unfortunately this is what is playing out,” he said.
Burgess said his agency did not believe any of the alleged terrorism plots it had investigated in the past year had been inspired by the Gaza conflict.
He reiterated that Gaza was “not the cause” of the threat level rising, but was “a significant driver”.
“It’s driven more emotion and heat into society,” the Asio chief said.
Burgess acknowledged it was not Asio’s job to intervene in lawful protest movements.
“Lawful dissent, lawful protests are fine,” Burgess said. “It’s the people who think violence is the answer – not just because of Gaza, though. In this current environment, violence is more likely at protests.”
Burgess said an escalation of the conflict, including between Israel and Hezbollah in Lebanon, would inflict “further strain”.
Asked by a reporter whether any particular groups, including Jewish Australians, were more at risk of being targeted, Burgess said it was “across the board”.
“Yes, there’s plenty of antisemitism but there’s plenty of Islamophobia at the same time. It’s kind of an almost equal treatment, not quite, but almost equal treatment.”
Asked about the practical impact of the decision to increase the threat level, Burgess said authorities would review their previous assessments of individuals as to whether they might resort to violence.
Earlier on Monday, intelligence sources who asked not to be named said the concerns spanned a range of ideologies, including people taking “a perverse” interpretation of Islam, neo-Nazis, anti-globalist and anti-authority types, and others with personal grievances.
The sources said an erosion of trust in government and democratic processes was “endemic across western nations”. They pointed to the UK, where far-right riots have broken out in the past week.
