A shoe was thrown at Norwegian mass-killer Anders Breivik by the brother of one of his victims at his trial on Friday.
"You killed my brother! Go to hell!" shouted the man from the Oslo courtroom, a few meters from the defendant, reports said.
The shoe apparently missed Breivik and hit his lawyer. The trial was interrupted by the incident, and was scheduled to resume on Friday afternoon.
The BBC reported "spontaneous applause" after the incident from any of those in the courtroom.
Breivik has admitted killing eight people in a bomb attack on Oslo, and shooting dead 69 others including many children at a political youth camp on Utoya island, on 22 July 2011.
The 33-year-old denies his is criminally responsible for the killings, and said the political camp was a fair target because of the country's Labour Party's multicultural policies.
It is thought that the trial is centred on whether he will be legally declared insane, as it will determine if he is sent to prison for a maximum of 21 years or a psychiatric institution.
The court has been hearing from survivors of the attacks on Utoya, with many members of the public and victims' families left in tears by the testimony.