A national memorial is being held in Norway today for victims of last month's twin terrorist attacks in which 77 people were killed.

The ceremony is taking place at the Spektrum arena in Norwegian capital, Oslo, and marks the end of an official month-long period of mourning.

Tributes will be paid to the victims and survivors, as well as the emergency service personnel who were involved in the rescue operation.

The ceremony is being attended by King Harald and Prime Minister Jens Stoltenberg, who will deliver addresses.

There will also be a rare performance from Aha, one of Norway’s most successful music acts.

The memorial comes at the end of a difficult weekend for survivors and close friends and family of the victims, who have been visiting the scene of the massacre on Utoeya island and the car bomb in Oslo.

Around 500 mourners made the solemn visit to Utoeya island over the weekend, where they were shown the exact spot where their loved ones were killed by Anders Behring Breivik.

Breivik has admitted carrying out the massacre and planting a bomb in Oslo that killed eight people. He has been placed in solitary confinement while the police continue their investigation.

Relatives of the Oslo car bomb victims have also visited the scene of the attack.