Two psychiatrists tasked with examining the perpetrator of the worst attacks carried out in Norway since World War II handed over their findings on Tuesday: the 32-year-old right-wing extremist Anders Behring Breivik suffers from "paranoid schizophrenia".

Their diagnosis, which signifies that he most likely will be sentenced to receive psychiatric care in a closed institution — possibly for the rest of his life — instead of prison, has sparked vivid debate in Norway and has especially set internet message boards ablaze.

"The worst mass murderer in the world absolved. Nowhere else but Norway," someone using the pseudonym Juletissen wrote on a message board hosted by the VG daily.

"Breivik is unaccountable and a paranoid schizophreniac. One could certainly have said the same thing about Hitler and Stalin," Ingeborg Vea chimed in on the Twitter microblogging site.

In the streets of Oslo, reactions were more moderate.

"Only a crazy person could do something like this," Sten Ture Jensen, a 55-year-old investor, told AFP.

"In a state with the rule of law, we have psychiatrists who are asked to reach a conclusion and we have to respect their opinion," he added.

A poll conducted for public broadcaster NRK shortly after the diagnosis was announced indicated that 36 percent of Norwegians think closed psychiatric care for Breivik would be an appropriate judicial response, while 48 percent do not.

"It is sad that so many people see the (psychiatrists') conclusion as an excuse when it is simply an explanation," high school student Celina Gulthe told AFP.

Her friend Synne Midtboe agreed.

"It doesn't matter whether he is locked up in a psychiatric institution or in a prison, as long as he is locked up," she said.

"But for him, who thought he was a great thinker, he must be furious to have been declared insane," she added.

In effect, Behring Breivik was deeply unhappy with the conclusion when he received word of it Tuesday evening, according to prosecutor Christian Hatlo.

"It appears he is not ready to accept this and that he feels insulted," Hatlo told the NTB news agency.

"He was a bit surprised but at the same time he said he had been expecting the worst," one of the confessed killer's lawyers, Odd Ivar Grøn, told AFP.

The populist right-wing and anti-immigration Progress Party, which once counted Behring Breivik as a member, meanwhile questioned how someone insane could plan such elaborate attacks over several years and carry them out, demanding a new evaluation of the gunman.

Most other political parties however expressed confidence in the Norwegian judicial process.

"It is up to the courts to judge, not politicians," Prime Minister Jens Stoltenberg insisted.

His Labour Party was the target of the July 22nd twin attacks, since Islamophobe Behring Breivik accused it of promoting the multicultural society he despised.

In a single day he first set off a car bomb outside government buildings in Oslo, killing eight people, before going on a shooting rampage on the nearby island of Utøya, where the Labour Party youth organisation was hosting a summer camp.

For nearly an hour and a half, he methodically killed another 69 people, most of them teenagers.

Most of the lawyers of survivors and family members of the victims have reassured their clients that there is very little chance Behring Breivik will ever be released.

"The fact that Anders Behring Breivik is declared criminally insane does not change much," Norway's paper of reference, Aftenposten, wrote on Wednesday.

"He will be locked up. For a long time."