The death toll from the massacre in Norway is expected to rise still further today as British police stand ready to help detectives investigating the bomb attack and mass shooting.
Home Secretary Theresa May said she had spoken to Norwegian justice minister Knut Storberget and offered him any assistance needed.
She joined a series of senior political figures and the Queen in expressing sympathy in the wake of Friday's attacks.
David Cameron said yesterday it was important for Britain to learn any lessons it could from the outburst of violence.
He said: "The loss of life in Norway has been absolutely horrific; it's on a scale, frankly, that is hard to comprehend.
"The Norwegians are old friends and allies and neighbours of Britain, and I know that everyone in Britain will want to stand with the Norwegian people in the days of sorrow that lie ahead.
"Also, we will want to make sure that we learn, like others, any lessons there are to learn about how to be more secure against horrific outrages like this, and that's something we can discuss at the National Security Council on Monday."
On Friday a bomb exploded at a high-rise building in Oslo that houses the offices of prime minister Jens Stoltenberg, who was not in the building at the time.
A gunman dressed as a policeman then opened fire on young Labour supporters at a summer camp on the island of Utoya. The death toll from both attacks is at least 92, but there are still at least four or five people missing from the shooting incident.
Mrs May said: "I made clear to Minister Storberget that we will help in any way we can. In particular I offered police assistance, which we stand ready to provide, should Norway request it."
The Queen wrote to King Harald of Norway to say that she was "deeply saddened and shocked by the tragic loss of life" and voiced her "heartfelt sympathy".
Labour leader Ed Miliband called the attacks "an affront to decent people" and London mayor Boris Johnson contacted his counterpart in Oslo to say he was "shocked and saddened" at the chilling events.
The suspected gunman, Norwegian Anders Breivik, 32, was preliminarily charged yesterday with acts of terrorism.
His defence lawyer Geir Lippestad told broadcaster NRK that Breivik had "confessed to the factual circumstances".
Mr Lippestad said his client had also made some comments about his motives but "I don't want to talk about it now".
It is claimed that he beckoned to his young victims before shooting them one by one. Breivik is reported to hold Christian fundamentalist views.
Agricultural supplier Felleskjopet said he bought six tonnes of fertiliser in the weeks before the attack. The material can be used in home-made bombs.
According to reports, the suspect wrote a 1,500-page manifesto before the attacks in which he criticised multi-culturalism and Muslim immigration.
Police are investigating witness accounts that there may have been a second gunman on the holiday island.
Hundreds of young people were attending the summer camp organised by the youth wing of Mr Stoltenberg's Labour Party.
He told reporters: "This is beyond comprehension. It's a nightmare. It's a nightmare for those who have been killed, for their mothers and fathers, family and friends."
Meanwhile, it has emerged that police arrived on the island an hour and a half after the gunman first opened fire, because they did not have quick access to a helicopter and could not find a boat to reach the scene just several hundreds yards away.
The assailant surrendered when police finally reached him on Utoya, but 82 people died before that.
Chilling accounts have emerged of what happened at the camp.
A 15-year-old, Elise, said she heard gunshots but then saw a police officer and thought she was safe. Then the man started shooting people in front of her.
"I saw many dead people," she said.
"He first shot people on the island. Afterwards he started shooting people in the water."
Emilie Bersaas, one of the youths on the island, said she ran inside a school building and hid under a bed when the shooting started.
"At one point the shooting was very, very close (to) the building, I think actually it actually hit the building one time, and the people in the next room screamed very loud," she told Sky News.
"I laid under the bed for two hours and then the police smashed a window and came in. It seems kind of unreal, especially in Norway. This is not something that could happen here."
Vessels visiting Lerwick in Shetland as part of the Tall Ships Races are flying their ensigns at half mast as a mark of respect.
The ships leave tomorrow for Stavanger in Norway, which is the next stage in the race.