Breivik, who stands accused of killing at least 76 people in a bomb attack in central Oslo and a shooting rampage on the nearby island of Utøya on Friday, told the court hearing he had "two further cells" in his organisation, according to the court registrar.
Judge Kim Heger ordered the Norwegian twin attack suspect to be remanded in custody for eight weeks, following the 32-year-old man’s not guilty plea.
Breivik will remain in solitary confinement for the first half of his remand, with a ban on all communications with the outside world in a bid to aid a police investigation into his acts.
“There is an immediate risk that the accused would tamper the evidence if he were now released,” said Judge Heger at a press conference following Breivik’s first hearing on Monday.
Judge Hedger added that the 32-year-old suspect confessed to carrying out the twin attacks, but refused to acknowledge his guilt.
Breivik said the killings had been necessary to prevent Europe being taken over by Muslims.
His declared objective had been to inflict the greatest possible loss on Norway’s governing Labour Party, which he blamed for encouraging immigration.
At least eight people died in Friday’s initial car bombing outside the prime minister’s office, in a calculated distraction for police allowing Breivik to shoot at least 68 youngsters attending a summer camp on the island of Utoeya, 40 kilometres away.
Norway’s maximum prison sentence is 21 years but the attacks have triggered calls for the country to reinstate the death penalty.
“This isn't just another event. This is something extremely serious that requires a response, a European response, a shared response to defend freedom, to defend democracy, calling on people to rise up and fight radicalism, to respond against xenophobia,” announced Spain’s prime minister José Luis Rodríguez Zapatero in a joint news conference with Britain on Monday.