Prime Minister Jens Stoltenberg said Sunday that right-wing extremist Anders Behring Breivik, who massacred 77 people a year ago, failed in his attempt to change Norwegian society.
"The bomb and bullets were aimed at changing Norway. The Norwegian people responded by embracing our values. The killer failed, the people won," Stoltenberg said at a ceremony marking the first anniversary of the massacre.
Exactly a year ago Breivik set off a bomb outside government buildings in Oslo, killing eight people, before going on a shooting rampage on nearby Utoeya island, where the governing Labour Party's youth wing was hosting a summer camp.
He killed 69 people on the island, most of them teens, with the youngest having just celebrated her 14th birthday.
The extremist, now 33, said he carried out the attacks to protect his country against "the Muslim invasion" and said he had targeted the Labour Party for its immigration policies and support for a multicultural society.
The Labour prime minister, who was at his official residence and not in his office at the time of the attacks, kicked off Sunday's commemorations by laying a wreath near the spot where the bomb went off.
Religious services, wreath-laying ceremonies, commemorative gatherings and a concert were planned across the country to mark the anniversary.
Stoltenberg will attend many of the most heart-wrenching events commemorating the worst atrocity carried out on Norwegian soil since World War II.
The prime minister made a deep impression shortly after the massacre with his vow that Norway's response to the bloodbath would be "more democracy, more openness and more humanity, but never naivety."
Stoltenberg will attend, along with Norway's king and queen, a service at the city's cathedral, which in the weeks after the attacks was surrounded by an ocean of roses left by mourners.
At 2:10 pm (1210 GMT), he will give a speech for Labour Party youth on Utoeya before meeting with family members of Breivik's victims and laying a second wreath on the island at 6:45 pm - almost exactly the time that Breivik was finally arrested there after his more than hour-long shooting spree.
To wrap up the emotional day, Stoltenberg is set to attend a commemorative concert outside the Oslo city hall featuring mainly Norwegian musicians and possibly Bruce Springsteen, starting at 8:00 pm.
Norwegian folk singer Lillebjoern Nilsen, who in April led some 40 000 rose-waving protesters to sing a song derided by Breivik, will also perform.
Roses, the symbol of Breivik's main target, the Labour Party, are expected to be omnipresent, while Norway's professional football teams will observe a minute of silence before all games played Sunday.
The Labour prime minister in neighbouring Denmark, Helle Thorning-Schmidt, is also scheduled to speak on Utoeya, while US Secretary of State Hillary Clinton has delivered a message of sympathy to the Norwegian people for this "enormous tragedy."
Eskil Pedersen, who heads the Labour Party youth wing and who escaped Utoeya at the beginning of the shooting massacre, last week hailed Norway's reaction to the tragedy.
"There are ... a few things that have developed in the right direction," he told the NTB news agency, saying he was especially pleased that political youth groups had seen their membership numbers soar.
"We have more democracy now because more people are participating," he said.
Breivik, whose 10-week trial ended last month, is meanwhile awaiting his verdict.
While there is no doubt he carried out the attacks, the five Oslo court judges must decide whether he should be considered criminally sane and sentenced to prison, as requested by his defence, or instead follow the prosecution's line and send him to a closed psychiatric ward.
The verdict is expected on August 24.