"I hope you will focus on the issue, not the person," the 33-year-old Breivik told the court, visibly irritated and swivelling a pen in his hand.

Breivik, who killed eight people with a car bomb in Oslo on July 22 and then shot 69 at a Labour Party summer camp, went on trial on Monday.

Asked how he had changed from a teenage vandal on Oslo's prosperous west side to a methodical killer, he said he helped found a militant group called the "Knights Templar" in 2001 and chafed at prosecution suggestions that it was largely imaginary.

"Your intention is to sow doubt whether this network existed," he said at one point, after repeatedly objecting to the way prosecutors phrased their queries.

The original Knights Templar were a medieval brotherhood of knights that prosecuted and financed anti-Islamic crusades.

Breivik has pleaded not guilty to terrorism and murder charges on grounds of "necessity". He called his victims "traitors" with immigrant-friendly ideas.

After the attacks the police tried to confirm Breivik's claim that he had allies plotting new actions. Security agencies across the West turned attention to right-wing extremists, but Norway's police said they concluded Breivik was a lone wolf.

Breivik said he met his first "militant nationalist" in London in 1999, when he was about 20, and several more in 2001, after an adolescence marked by confrontations with Muslim youths from the other side of Oslo.

"I searched toward European militant nationalists," he said. "The militant nationalist community in Norway has a lot of surveillance."

On Tuesday, his first day of direct testimony, he said the Sept. 11, 2001, attacks by Al Qaeda on the United States were key to his radicalisation and that his main source of information was Wikipedia, the open-source online encyclopedia.

When he went to Liberia in 2001 to meet a Serbian nationalist he had two covers, he said on Wednesday, one as a worker for UNICEF, the U.N. children's organisation, and the other as a blood-diamond smuggler carrying a magnifying glass.

From Liberia he travelled to London to meet three other nationalists, people whose names he refused to provide.

"I don't want to give any information that would make other people apprehended," he said.

He admitted on Tuesday that his previous descriptions of the Knights Templar" were a "pompous" exaggeration with a kernel of truth.

"Instead of telling about four sweaty guys in a cellar, or some other locale, you use other ways of description," he said, referring to a 1,500-page written screed and early conversations with psychiatrists in which he implied the secret group was large and powerful.

He said that since 2002 he has had little contact with the people he met in London, and that the "cell" he commands consists of himself alone.

Since Breivik admits the July 22 attacks, his trial will turn on the question of his sanity and thus whether he can be sentenced to prison or to a psychiatric institution.

An initial court-appointed team of psychiatrists concluded he was psychotic, while a second team found him to be of sound mind.