Police confirmed another person had died after the gunman opened fire at a summer youth camp on Friday.
The 86th victim of the shooting spree is understood to have died in hospital, while seven died in the bombing.
Police have been investigating the background of the suspect, Anders Breivik, who was charged with terrorism following the blast in downtown Oslo and gun attack on the island of Utoya.
Asked if they were exploring possible links to British extremist groups, a spokesman said: “I’m sure they will do. They are following every lead and they’re checking out everything he might have been associated with.”
It was too early to say which groups this might include, he added.
But reports suggested Breivik had connections and sympathies with the right-wing English Defence League (EDL).
A manifesto he published online, said to have been posted the day of the attack, railed against Muslim immigration to Europe and vowed revenge on “indigenous Europeans,” whom he accused of betraying their heritage. He added that they would be punished for their “treasonous acts”.
The EDL denied that Breivik, 32, had any links with it and said it “vehemently” opposed his actions.
In a statement on its website the group wrote: “Terrorism and extremism of any kind is never acceptable and we pride ourselves on opposing these...
“We strongly oppose extremism and always reject any suggestion of us being either extremists or far-right, due to our great past record of dealing with anyone who holds such extremist views.”
The Nordic Defence League also distanced itself from the killings, posting a message on its Facebook page saying: “We condemn this act of terror no matter who or where this came from! Our duty is to react rational only in democratic ways.”
Breivik’s lawyer said his client had wanted to revolutionise Norway’s society and had “confessed to the factual circumstances” of the atrocities but denied criminal responsibility.
Geir Lippestad told Norwegian broadcaster NRK: “He wanted a change in society and, from his perspective, he needed to force through a revolution. He wished to attack society and the structure of society.”
A memorial service was held at Oslo Cathedral this morning as the nation mourned its dead and braced itself for the number of victims to rise still further.
King Harald, his wife Queen Sonja and the prime minister Jens Stoltenberg visited grieving relatives of the young people gunned down, while buildings around the capital lowered their flags to half-mast and people streamed to the cathedral to light candles and lay flowers.
Flowers and candles were also placed outside the Royal Norwegian Embassy in London, which remained open today to provide support to anyone who needed it, its flag flying at half-mast.
A spokesman said: “People have come to the embassy to express their sympathies. I read some of the notes they left and some were in Norwegian but most were in English.”
Meanwhile extra security was planned for mosques around the UK in the wake of the deadly attacks.
Mohammed Shafiq, the leader of Ramadhan Foundation, one of Britain’s largest Muslim groups, said mosques were being extra vigilant and he had spoken to police about extra protection.
“People are afraid that we will be the next target,” he said. “As a result, we’ve told people to be extra vigilant and there will be added security placed at mosques.”
The attacks began on Friday when a bomb exploded at a high-rise building in Oslo that houses the offices of the prime minister, who was not there at the time.
A gunman dressed as a policeman then opened fire on young Labour supporters at the summer camp on Utoya.
More than 90 people were injured, with at least four or five people missing from the shooting incident.
Agricultural supplier Felleskjopet said the suspect bought six tonnes of fertiliser in the weeks before the attack. The material can be used in home-made bombs.
Police were investigating witness accounts that there may have been a second gunman on the holiday island.