Berlin police have advised residents to stay at home after a truck ploughed in a Christmas market, killing at least nine people and hurting many more.

The announcement was made on Twitter.

Police also urged people not to "spread rumours about the event".

Officials have said the event will be investigated as a terrorist attack and that they have arrested the driver.

Another person was found dead in the lorry, which was reportedly hijacked as it drove to Germany from Poland.

Chancellor Angela Merkel was being briefed by the Interior Minister and Berlin mayor on the situation, a government spokesman said.

Facebook activated its 'Safety Check' feature so its users in the city could identify as safe to family and friends.

However, police said there were no further indications of "dangerous situations" elsewhere in the city.

The authorties urged people to stay away from the area.

Berlin Christmas market lorry attack Show all 18 1 /18 Berlin Christmas market lorry attack Berlin Christmas market lorry attack Several people have been killed after a lorry drove into crowds at a Christmas market in Berlin REUTERS/Fabrizio Bensch Berlin Christmas market lorry attack 'At least nine' people have been killed and more than 50 injured. AP Berlin Christmas market lorry attack Emergency Services rush a Berlin market victim to an ambulance Associated Press Berlin Christmas market lorry attack Police cordoned off the square at Kaiser Wilhelm Memorial Church following the incident REUTERS Berlin Christmas market lorry attack Rescue workers inspect the lorry that crashed into a Christmas market close to the Kaiser Wilhelm memorial church in Berlin EPA Berlin Christmas market lorry attack Emergency crews inspect the lorry that ploughed into a Berlin Christmas market, killing at least nine people AFP Berlin Christmas market lorry attack Fire crews attend the scene of the attack AFP/Getty Berlin Christmas market lorry attack Armed police secure the site of a lorry attack at a Christmas market in Berlin REUTERS Berlin Christmas market lorry attack Crushed debris is visible beneath the wheels of the vehicle REUTERS Berlin Christmas market lorry attack An injured man is pushed to an ambulance REUTERS Berlin Christmas market lorry attack Medics attend an injured person after the lorry attack which killed at least nine and injured more than 50 people AFP/Getty Berlin Christmas market lorry attack Firefighters examine the lorry which was rammed into a Berlin Christmas market REUTERS Berlin Christmas market lorry attack A person is carried into an ambulance REUTERS Berlin Christmas market lorry attack View of the lorry that crashed into a Christmas market in Berlin, killing at least nine and injuring at least 50 people AFP/Getty Berlin Christmas market lorry attack Rescue workers push a person on a stretcher to an ambulance Getty Berlin Christmas market lorry attack Firefighters assess the damage after the lorry rammed the Christmas market, killing 'at least nine', and injuring more than 50 people AP Berlin Christmas market lorry attack Firefighters stand beside a toppled Christmas tree at the site of the suspected terrorist attack in a Berlin Christmas market AP Berlin Christmas market lorry attack Damaged stalls at the scene of the incident at a Berlin Christmas market where at least nine people have been killed EPA

Mike Fox, a tourist from Birmingham, England, told The Associated Press at the scene in Berlin that the large truck missed him by about three meters as it drove into the market, tearing through tables and wooden stands.

"It was definitely deliberate," Mr Fox said, adding that he helped people who appeared to have broken limbs, and that others were trapped under Christmas stands.