In his first court appearance since his arrest on Friday, Anders Behring Breivik admitted he was responsible for Norway's worst atrocity since World War Two but pleaded not guilty, according to Sky News.

In a statement he said he had carried out the attacks because he wanted to "save Norway and Western Europe from a Muslim takeover".

He accused the Labour party of "mass imports of Muslims" and said the objective behind the terror plot was to give a "sharp signal to the people".

The 32-year-old said his bombing of government buildings in Oslo and massacre at a summer camp on Utoya island for Labour's youth wing was aimed at deterring future recruitment to the Labour party.

Judge Kim Heger said Breivik's claim that he had accomplices needs further investigation.

He had previously said he was acting alone and police currently have no other suspects.

But in a press conference officers said they "cannot completely rule out that someone else was involved".

Friday's tragedy started when Breivik set off a car bomb near government headquarters in Oslo.

Police have said the number of people killed in the blast has increased to eight, with a further 30 injured.