OSLO: Religious services, wreath-laying ceremonies, commemorative gatherings and a concert are scheduled across Norway Sunday on the first anniversary of twin attacks that killed 77 people.

On July 22, 2011 right-wing extremist Anders Behring Breivik first set off a bomb near the government building in Oslo, killing eight people, before going on a shooting rampage on nearby Utoeya island, where the ruling 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.

Numerous events are scheduled in and around Oslo, and especially at the sites of the two attacks, in memory of the victims of the worst atrocity carried out on Norwegian soil since World War II.

Religious services and commemorative gatherings will also be held from the very south of the country to the Arctic archipelago of Svalbard, some 1,100 kilometres (700 miles) from the North Pole.

Prime Minister Jens Stoltenberg, who 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”, will be present at many of the the most heart-wrenching events.

The Labour Party leader is scheduled to lay a wreath at the site of the Oslo bombing at 9:30 am (0730 GMT) before attending, 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, the prime minister 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 emotionally trying day, Stoltenberg is set to attend a commemorative concert outside the Oslo city hall featuring mainly Norwegian musicians and, perhaps, 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 there.