Norwegian mass killer Anders Breivik has left journalists, family members and survivors in tears after telling a courtroom of his deadly rampage in horrific detail.
Breivik advised people to leave the courtroom, which few reportedly did, before embarking on a highly detailed 90-minute discussion of the Utoya island killings.
There were tears in the eyes of those present on the fifth day of his trial for killing 77 people as he described shooting teenagers "paralysed with fear", reported the Guardian.
Breivik said he could "not remember smiling" during the attacks. He also described "sparing" a boy who was weeping hysterically because he was "too young".
His "enthusiastic" testimony included his memory of firing at children attempting to make themselves invisible against the edge of cliffs, calmly shooting a boy in the head as he listened to his iPod.
Breivik also claimed he attempted to call the police to surrender, but couldn't get through so carried on killing.
Earlier he told the courtroom "under normal circumstances I am a very nice person".
The 33-year-old shocked the court when described deliberately "dehumanising" himself in a five year programme of preparation for the attacks, reports the BBC.
When asked by the victims' lawyer why he was not showing any empathy, Breivik said he was putting up a "mental shield" to protect himself.
"I can choose to remove the mental shield, but I am choosing not to do it... because I would not survive," he said, reports AP.
He described his acts as "gruesome and barbaric" and said that using technical language to describe his strategy allowed him to carry on with his testimony.
Onlookers on Monday were stunned when he performed a far-right salute upon entering the courtroom. However Breivik has now agreed to a request from his own lawyers to drop the salute, after families of his 77 victims urged the Norwegian killer to stop the gesture.
Prosecutors showed images of Breivik taken from his manifesto. A badge on the uniform read "Marxist Hunter"
Officials organising the trial have decided not to broadcast footage of him giving his testimony, focussing only on the courtroom. Some Norwegian newspapers have taken the decision not to post any pictures of him while he delivers his defence.
Describing al-Qaida as "inspirational" he said that in the run up to 22 July he studied the group's attack on the World Trade Centre as well as far-right extremist Timothy McVeigh, who carried out the Oklahoma city bombings in 1995, killing 168 people.
He said he scoured the Internet for bomb making guides, telling the court: "I have studied each one of their actions, what they have done wrong, what they have done right".
During the trial he told the judge: "I do not recognise the Norwegian courts"
Breivik planted a car bomb outside government buildings in Oslo, killing eight people on 22 July last year. After the bomb exploded, he drove to the island of Utoya, where he opened fire on a Labour youth camp, killing 69 people.
On Thursday, Breivik told the court he also planned to execute Norway's former Prime Minister Gro Harlem Brundtland, who had visited the island ahead of the massacre, adding he wanted to post a film of her beheading online.
As Breivik has admitted to the killings, the trial is focused on whether or not the killer is sane. His defence team have said the extremist would like to be found legally sane.
Breivik faces a 21-year jail sentence if found guilty. He said: "I consider 21 years of prison as a pathetic punishment."
Norway does not carry the death penalty.
The killer has maintained he carried out the attacks to protect Norway from being taken over by Muslims. He told the court on Tuesday he "would do it all again because he was motivated by goodness, not evil."