Tunisian man sought for Berlin truck attack

German police on Wednesday said they were searching for a Tunisian man in connection with Monday evening's truck attack. The Federal Prosecutor's Office announced a reward of 100,000 euros for information leading to the suspect's arrest.

A truck ploughed into a crowd at a Christmas market in Berlin leaving 12 people dead and 48 injured. Asylum papers believed to belong to the suspect were found in the back of the truck.

Ralf Jaeger, interior minister of the western state of North Rhine-Westphalia (NRW), said the man appeared to have arrived in Germany in July 2015 and his asylum application had been rejected.

He seemed to have used different names and had been identified by security agencies as being in contact with an "Islamist network". The man had mainly lived in Berlin since February, but was recently in NRW, Jaeger said.

The man had been considered a potential threat by security authorities since November. After being turned down for asylum, he should have been deported but could not be returned to Tunisia because his documents were missing, added Jaeger.

"Anis AMRI is 178 cm tall and weighs about 75 kg, has black hair and brown eyes," the Federal Prosecutor's Office said in the statement. "Beware: He could be violent and armed!" Two pictures of Amri were published on the GBA's website.

On Tuesday, Daesh claimed responsibility, saying "a soldier of the Islamic State carried out the attack."

"There is much we still do not know with sufficient certainty but we must, as things stand now, assume it was a terrorist attack," German Chancellor Angela Merkel said.

"True perpetrator can cause fresh damage"

Earlier, police released a Pakistani asylum seeker who was taken in for questioning. Berlin's police chief admitted the mistake.

"We have the wrong man," Die Welt newspaper quoted the police chief as saying, "And therefore a new situation. The true perpetrator is still armed, at large and can cause fresh damage."

"Attacker will be punished with all means possible"

Merkel has promised that every detail will be clarified and the perpetrator will be punished with all the means possible.

"I know it would be especially hard for us all to bear if it were confirmed that the person who committed this act was someone who sought protection and asylum," she said on Tuesday morning.

If a migrant link is confirmed, it could further sour sentiment towards asylum-seekers in Germany, where more than a million people fleeing conflict and poverty in the Middle East, Africa, and elsewhere have arrived this year and last.