German Chancellor Angela Merkel has said "we must assume" the deaths of at least 12 people at a Christmas market in Berlin "was a terrorist attack", saying it would be "repugnant" if it was true that a refugee was responsible.

A truck drove into the crowd at the market, injuring some 48 other people. A man has been detained in relation to the incident, which police believe may have been a deliberate act.

However the suspect, identified as a 23-year-old Pakistani refugee called Naved B, has reportedly denied involvement in the incident.

According to a live translation of her remarks at a press conference, Ms Merkel said: "We don't know anything for certain, but we must assume it was a terrorist attack.

"It would be very difficult for us to learn that a human being who came to Germany to ask for refuge and asylum committed this deed.

"It would be terrible for all Germans who are very active, day by day, in helping asylum seekers and refugees.

"It would be repugnant for those who are helping people who came to this country asking for our help."

Ms Merkel said she was "shocked and very saddened" by what had happened.

"Twelve people who were among us yesterday, who were looking forward to Christmas and who had plans for the festive season, are no longer among us," she said.

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

"It is a terrible deed which one cannot understand. It took their lives. Many people are injured, are fighting for their lives and their health.

"In these hours, first and foremost I think of these people, the dead, the injured, their families and friends. The whole of the country is with you in deep sadness."

Saying she would visit the site of the alleged attack and also hold a meeting of her security cabinet, Ms Merkel urged people not to allow terrorism to change their way of life.

"Millions of people, including myself, are asking ourselves, how can you live with the fact that, while celebrating the festive season where we want to celebrate life, somebody has come along and taken so many lives. I only know that we do not want to, and we cannot live with it," she said.