German Chancellor Angela Merkel has made a speech apologising for the authorities' failure to tackle a neo-Nazi group that went on a murder spree, killing 10 people and eluding capture for more than a decade.

Speaking at a memorial event held at a Berlin concert house, attended by officials and relatives of the victims, Merkel said the far-right killings were "a disgrace for our country". As some of the victims' relatives were unjustly suspected in the murders, she told them: "I ask for forgiveness."

The neo-Nazi group National Socialist Underground (NSU) killed eight Turks and one Greek, all shopkeepers or food vendors, from 2000 to 2006. They then shot a policewoman in Helibronn in 2007.

Their activities went undetected until November, when a failed bank robbery led to two of its three members committing suicide and the survivor surrendering to police.

The killings gave rise to fury and mistrust among the 15 million members of Germany's immigrant community and their families.

The daughter of one of the victims, 25-year-old Semiya Simsek, also spoke during the memorial service. She was born and raised in Germany, but plans to leave the country because she cannot deal with knowing her father was murdered because he was not German.

"We could not grieve in peace," she said. "We couldn't be simple victims. There was always the suspicion that someone in the family could have been responsible, or that my father [Enver Simsek] might have been a criminal."

Merkel has previously referred to the case as "a shame for Germany" and vowed at a party conference in Leipzig to "do everything possible to bring justice to the people".

The German government previously offered each family compensation of at least €10,000 (£8,500) in an effort to redress the situation and show the country's openness to immigrants.

Twelve candles were lit in tribute to the victims, one for each person who died, one for all victims of right-wing violence and one for "shared confidence and hope".

The ceremony was followed by a nationwide minute of silence.