OSLO, Norway – Norwegians who lost loved ones on Utoya island relived the horror Friday as far-right fanatic Anders Behring Breivik described in harrowing detail how he gunned down teenagers as they fled in panic or froze in fear before him.

Survivors and victims’ relatives hugged and sobbed, trying to comfort each other during the graphic testimony.

“I’m going back to my hometown tonight. My husband, he’s going to drive me out to the sea, and I’m going to take a walk there and I’m going to scream my head off,” said Christin Bjelland, whose teenage son survived the attack.

Breivik’s defense lawyers had warned their client’s testimony would be difficult to hear. Still, the shock was palpable in the 200-seat courtroom as the self-styled anti-Islamic militant rolled out his gruesome account, without any sign of emotion.

A man who lost a son squeezed his eyes shut, his pain palpable. A man to his left put a comforting hand to his shoulder, while a woman to his right clutched onto him, resting her forehead against his arm.

Tore Sinding Bekkedal, a 24-year-old survivor of the massacre, left the courtroom during Breivik’s testimony.

“I could not care less about what he says or the way he says it,” Bekkedal said. “I do not care about him as a person.”

Breivik has confessed to the July 22 bombing-and-shooting rampage that killed 77 people — 69 on Utoya and eight in Oslo. But he rejects criminal guilt, saying the victims had betrayed Norway by embracing “Islamic colonization.”

Looking tense but focused, Breivik spoke calmly about the shooting rampage, beginning with a ferry ride to the island, where the governing Labor Party holds its annual summer youth camp. He was disguised as a policeman, carrying a rifle and a handgun. He also brought drinking water because he knew he would become parched from the stress of killing people.

Breivik’s first victims were Monica Boesei, a camp organizer, and Trond Bentsen, an off-duty police officer and camp security guard.

“My whole body tried to revolt when I took the weapon in my hand. There were 100 voices in may head saying ‘Don’t do it, don’t do it,’ ” Breivik said.

Nonetheless, he pointed his gun at Bentsen’s head and pulled the trigger. He shot Boesei as she tried to run away. Then as they lay on the ground, he shot them both twice in the head.

Breivik said the first shots pushed him into a “fight-and-flight” mode that made it easier to continue killing.

He couldn’t remember large chunks of the 90 minutes he spent on the island before surrendering to police commandos. But he recalled some shootings in great detail, including inside a cafe where he mowed down young victims as they pleaded for their lives.

Some teenagers were frozen in panic, unable to move even when Breivik ran out of ammunition. He changed clips. They didn’t move. He shot them in the head.

“They cannot run. They stand totally still. This is something they never show on TV,” Breivik said. “It was very strange.”

The main goal of the trial, now in its fifth day, is to determine whether Breivik was sane or insane — two medical evaluations have come to opposite conclusions.

“He’s completely emotionless,” said Paal Groendal, a psychologist who watched Friday’s hearing but was not among those who examined the confessed killer.

“He remembers details about smashed windows. But he doesn’t remember if it was a boy or girl he shot. … It seems like he doesn’t remember people. To him they are details,” Groendal said.

Breivik said his goal was to kill all of the nearly 600 people on the island.

“You will die today Marxists,” Breivik recalled shouting.