BERLIN • The Tunisian man who ploughed a truck into a Berlin Christmas market had lived under 14 aliases and was so well known to German officials that a key counter- terrorism committee discussed his case seven times - suggesting the scale of the missed opportunities to thwart the Dec 19 attack.

The fresh details about Anis Amri - who was shot dead in Italy four days after the attack - emerged during testimony in the regional Parliament of North Rhine-Westphalia, where the suspect once lived.

German officials had already said that Amri had previously been flagged as a terrorism threat.

But the state's Interior Minister Ralf Jaeger described for lawmakers in Dusseldorf how the Joint Counter-Terrorism Centre, an institution coordinating the work of Germany's security agencies, had discussed his case repeatedly.

He also said six months of surveillance had yielded nothing concrete, suggesting an operative highly skilled at hiding his resolve, or a failure in German law enforcement to adequately monitor him.

Speaking to reporters on the day of the hearing on Thursday, Mr Jaeger said German officials felt they did not have enough on Amri to detain him.

"We live in a legal state, where suspicion and hearsay do not suffice to take someone into custody," he said. "And I think that is a good thing. A legal state needs to demonstrate in a court-proof manner that someone is planning a concrete crime."

The case has become the latest example of stumbles by the European authorities in the handling of terrorism suspects and has fuelled more criticism of German Chancellor Angela Merkel's decision to open the door to more than a million asylum seekers, many of whom were inadequately screened, said security analysts.

After a string of attacks last year, she described Islamist terrorism last week as Germany's "greatest threat". The authorities are continuing the search for possible accomplices in the market attack.

WASHINGTON POST