A deadly truck crash in Berlin has sparked warnings that Australia needs to do more to prevent terrorists carrying out copycat acts on home soil.
Twelve people died and 48 others were injured when a semi-trailer ploughed into into a crowded Christmas market.
German police said last night that they believe the crash outside the Kaiser Wilhelm Memorial Church was on purpose and called it a suspected terrorist attack. Experts have likened it to the truck attack by a terrorist on crowds in Nice, France, where 86 people died while celebrating Bastille Day in July.
ANU visiting professor Clive Williams believes it's only a matter of time before a similar attack happens in Australia. He says local authorities need to ensure that vehicle barriers are in place on local streets whenever mass gatherings occur - including New Year's Eve celebrations and Anzac Day parades - to help prevent copycat attacks.
"It is going to require a bit of a management on the part of the authorities because this kind of attack can be mounted fairly easily.
"Perhaps what we have to do is limit the size of vehicles that can approach mass gatherings and put appropriate barriers in place."
Williams expects attacks involving heavy vehicles will become more common as it's easier for terrorists planning them to go unnoticed by police and intelligence agencies.
German police have arrested a man they believe was driving the truck, while another man who was a passenger was found dead at the scene.
Witnesses described scenes of panic and horror as the truck veered off the street just off the famous shopping street of Kurfrstendamm at around 8pm local time.
Emma Rushton, a tourist, told CNN: "We were enjoying the Christmas lights and mulled wine. We were ready to get up when we heard a loud bang, To our left we saw Christmas lights torn down and the top of an articulated lorry crashing through the stalls and through people.
"We wanted to get out as soon as possible. We wanted to get to a safe place. In my opinion, it was going at 40m/h (65km/h), there was no sign it was slowing down. It did not feel like an accident ... The stall where mulled wine was being served was crushed. I saw people bleeding, lying in the pavement."
Mike Fox said the lorry missed him by around 3m. "It was definitely deliberate," he said. He added that he helped people who appeared to have broken limbs, and that others were trapped under Christmas stands.
The truck, which came from Poland, may have been hijacked. It is believed the passenger may have been the original driver of the truck. German authorities confirmed that the passenger was a Polish national.
Angela Merkel, the German Chancellor, expressed her sympathy for the victims.
The deadly crash comes five months after two Isis-inspired terrorist attacks in Germany, including one by a teenage Afghan refugee who used a knife and axe to wound five passengers on a train in Wuerzburg.
A 12-year-old boy with dual German-Iraqi citizenship also allegedly attempted to set off a nail bomb at a Christmas market in Ludwighafen, west Germany, two weeks ago after reportedly being inspired by Isis.
Some experts believe that terrorists behind the recent random attacks might be trying to inspire more recruits as Isis (Islamic State) comes under increasing pressure in Iraq and Syria, as well as instil fear across Western countries.
Part of the flow-on effect, though, could be a further rise in support for populist politicians. "These kind of terrorist attacks simply keep up a level of anxiety and feed into a particular perception of insecurity and maybe even stimulate support for rightist politics, populist politics," said Professor Michael Humphrey, of Sydney University.