Anders Behring Breivik who killed 77 people in twin terrorist attacks in Norway in July will be kept in solitary confinement for 4 more weeks, a Norwegian court ruled Friday.

The court dealing with Breivik's case took into account fears that Breivik could possibly "tamper with evidence" and that police had not been able to rule out if Breivik had accomplices, according to Judge Hugo Abelseth, as cited by DPA.

During his brief court hearing Breivik said the solitary confinement was "boring and monotonous, and a sadistic torture method", the judge said.

Breivik is thus to remain in solitary confinement until September 19, by which time a new custody hearing is due.

The ruling was announced a few hours after groups of bereaved arrived at the Norwegian island of Utoya where 69 people were killed in last month's shooting rampage in a visit aimed to help them cope with the loss of their loved ones.

"I think the visit means a great deal (for the bereaved), above all to see the place where their loved ones spent their last days and where they were found dead," Norway's Health Minister Anne-Grete Strom-Erichsen told broadcaster NRK, as quoted by DPA.

Strom-Erichsen said the bereaved families would be accompanied by a volunteer from the Red Cross and police officers on the island were tasked to show where loved ones were found.

In all 50 of the 69 immediately affected families have accepted to visit the island. Each family group was estimated to consist of about six people.

The visit for bereaved - and that planned for survivors of the July 22 attack on Saturday - was closed to the media.

Attorney Sigurd Klomset, representing some of the victims, told reporters that Breivik had 'not shown any remorse' and was mainly focused on his own fate during the hearing.

Breivik has said the July 22 attacks were necessary in order to change Norwegian society, and has expressed strong views against immigration, multiculturalism and Islam.

In addition to the shooting, he has admitted to detonating a car bomb that killed eight people in central Oslo.

On Sunday, a national memorial was to be held for the 77 victims. The last victim of the attacks was buried Thursday.