The trial began Monday of two men accused of killing popular Algerian singer Lounes Matoub but had to be twice suspended as his family interrupted to insist the suspects were innocent.

Matoub, who was known for upholding Berber culture and seeking official recognition of his people and their language, was gunned down aged 42 in Tala Bouinane, five kilometres (three miles) from the Kabylie capital Tizi Ouzou, east of Algiers, on June 25, 1998.

Two men, Malik Madjoun and Abdelhakim Chenoui, are on trial for the singer's murder but his family say others were responsible for the killing.

Monday's hearing in Tizi Ouzou was suspended for 30 minutes while the singer's sister Malika Matoub, his mother Aldjia Matoub and members of the Lounes Matoub Foundation chanted "Free Madjoun and Chenoui! Find the real perpetrators!" in the courtroom.

When the trial restarted a short time later, Malika Matoub interrupted proceedings to argue with the judge, shouting that the accused men had "nothing to do with" the case, resulting in the hearing being suspended for a second time.

She demanded that Hassan Hattab, a leader of the armed extremist Salafist Group for Preaching and Combat, who claimed responsibility for the killing, appear in court instead. Hattab gave himself up to police in October 2007.

Madjoun and Chenoui are part of a group of 10 people suspected of killing Matoub and have been in prison awaiting trial for the murder since 1998.

The other eight suspects are either on the run or have been killed by security forces.

Chenoui was taken out of the courtroom on Monday after he started shouting "I am innocent!"

One of the lawyers representing the accused men, Amine Sidhoum, told the courtroom: "I sympathise with the Matoub family and I ask that the trial continue despite the family walking out because two innocent people are in prison and have the right to be judged."

He added that it was "a disgrace for Algerian justice" that the men had been held without trial for so long.

Matoub's murder caused an uproar in Algeria and came during a civil war between Islamic extremists and the security forces.

Matoub's widow Nadia has blamed the Armed Islamic Group (GIA) for Matoub's death but his sister and mother believed there were other possibilities including a politically motivated killing.