A former state interior minister, Fritz Behrens, contested allegations of dismissing evidence of right-wing extremism prematurely during an investigation into a terrorist attack, when he appeared before a parliamentary committee in Berlin on Thursday. The committee has been tasked with scrutinizing German authorities' shortcomings in a prominent right-wing extremism case.

In 2004, members of an underground neo-Nazi terror cell, the National Socialist Underground (NSU), allegedly detonated a nail-filled bomb in Cologne, which injured 22 people. However, regional authorities quickly ruled out terrorist activity at the time, instead focusing the investigation into organized crime linked to the city's Turkish community.

Cologne is located in North Rhine-Westphalia - Germany's most populous state - where Behrens was serving as interior minister at the time of the attack.

"I apologize [for my misjudgement of the situation]," Behrens told the committee on Thursday.

According to Behrens, the evidence did not point to right-wing terrorism. But he admitted to making "fatal mistakes with disastrous consequences."

The committee's chairman from Germany's Christian Democratic Party (CDU), Clemens Binninger, said the authorities who had headed the Cologne probe, including Behrens, had probably missed the "biggest chance" of uncovering the NSU terror cell.

"This case had more evidence pointing to the NSU than any other," Binninger had said in an interview which appeared in Cologne's daily newspaper prior to the hearing.

German police first stumbled upon the terrorist cell last year when two of its members were found dead in an apparent double suicide following a botched bank robbery. The third member, Beate Zschäpe, was taken into custody and later indicted.

Between 2000 and 2007, the trio is alleged to have committed 10 separate murders of Turkish and Greek immigrants around the country, which authorities had attributed to local crime activity. Since then, revelations of file-shredding relating to these cases have also emerged, prompting the national inquiry into possible negligence of Germany's state police forces.

kms/mz (dpa, dapd)