German Chancellor Angela Merkel said it would be "particularly sickening" if the attacker who drove a lorry into a Berlin Christmas market turned out to be a refugee who had sought sanctuary in the country.

Twelve people died in the attack and at least 48 more were injured.

Ms Merkel also said she was "shocked, shaken and deeply saddened" by the event, which took place in a crowded tourist area.

"We don't know anything for certain, but we must assume it was a terrorist attack," she added. "It would be very difficult for us to learn that a human being committed this deed who came to Germany to ask for refugee and asylum."

A suspect arrested in connection with the attack has been named in local media as 'Naved B'. He is reported to be a 23-year-old refugee from Pakistan.

He had been living in Flughfen Tempelhof – an old airport that had been converted into a refugee centre – and was detained following the attack.

According to German radio station RBB-Inforadio,he arrived in in the country a year ago. He registered in Germany on 31 December 2015 in Passau, Bavaria.

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

Germany's open door policy on migration has allowed hundreds of thousands of refugees into the country, many from war-torn Syria.