An Australian woman has told of the terrifying moment she saw a truck plough into a crowded Christmas market in Berlin, killing 12 people and injuring 48 more.
Trisha O'Neill described seeing "blood and bodies everywhere" after the truck tore through the market beneath the historical Kaiser-Wilhelm Memorial Church ina suspected terrorist attack.
The 24-year-old Brisbane woman, who had moved to Germany in September, was sitting nearby drinking gluhwein with friends when the terror unfolded before their eyes.
Firefighters look at a toppled Christmas tree after a truck ran into a crowded Christmas market. Photo / AP
"I just saw this huge black truck speeding through the markets crushing so many people and then all the lights went out and everything was destroyed," she told the ABC.
"I could hear screaming and then we all froze. Then suddenly people started to move and lift all the wreckage off people, trying to help whoever was there."
O'Neill said she burst into tears when she saw how many people, including children, were laying on the ground.
"I never thought I would see something like this in my life," she said.
"I'm shaking and scared. It all just happened so fast."
Local police say they have arrested an alleged attacker, while another man, believed to be the passenger in the truck died at the scene.
Police armed with machine guns have been patrolling streets surrounding the church, which is one of Berlin's most famous landmarks and known as an anti-war memorial to peace and reconciliation.
A police officer with a submachine gun stands guard after a truck ran into a crowded Christmas market in Berlin. Photo / AP
Australian government officials are trying to establish whether any Australians were injured or killed.
Treasurer Scott Morrison said the attack was a horrible reminder, especially at Christmas which is supposed to be full of joy, of the evil that's out there in the world.
"It is not a very happy morning with these terrible events in Berlin," he told the Nine Network.
"We are thinking of those families in Berlin and hope that no Australians are affected."
The Department of Foreign Affairs is warning Australian travellers to avoid the area and remain vigilant in public places.
The overall level of advice for Germany remains unchanged, with travellers advised to exercise normal safety precautions and be aware of the increased threat of terrorism.
Anyone concerned about the welfare of Australians in the country can call the department on 1300 555 135 or the embassy in Berlin on 03 0880 0880.
