OSLO - Anders Behring Breivik roared a "battle cry" and appeared both angry and joyous as he shot people one by one with a distorted face, survivors of the Norwegian far-right killer's massacre told a court on Wednesday.

"I heard screaming but I couldn't make out the words," Ingvild Leren Stensrud, 17, who was shot in the leg and shoulder, said.

Stensrud, who survived after another victim fell on her, knocking her to the floor and creating the impression that she was dead, said she initially thought Breivik was not alone.

"I thought they (the attackers) were exchanging messages but realizing he was alone, I think the scream was actually a battle cry," she testified. Breivik made sure his victims were dead by delivering a control shot to their heads one by one, she added.

Breivik killed 77 people on July 22, first detonating a car bomb outside government buildings in central Oslo which killed eight, and then shooting 69 people, most of them teenagers, at the ruling Labour Party's summer camp on Utoeya Island.

He admits the killings but denies criminal guilt, arguing the killings were necessary since his victims were "traitors" who promoted Muslim immigration and multiculturalism, thereby threatening Norwegian ethnic purity.

Public reaction to the trial has been mostly calm, but days of harrowing testimony from survivors of Norway's worst peacetime massacre have raised tensions. Last week, the brother of a man gunned down by Breivik hurled a shoe at him in court.

One of the witnesses said that Breivik's "face looked distorted," said Waldenstroem, 20, who survived being shot in the face. "He looked angry and smiled simultaneously," he added, after asking the court to escort Breivik out of the room, saying he was unable to testify with him present.

If deemed sane, Breivik faces a 21-year jail sentence which could be indefinitely extended for as long as he is considered dangerous.

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