Anders Breivik has admitted killing 77 people in July 2011

Norwegian mass killer Anders Breivik has compared his "pain" to that of the families of the 77 people he killed.

In his final day of testimony at his murder trial for the killings, which he has admitted carrying out, Breivik said he lost contact with friends and family after the 22 July attacks.

"[I have] lost absolutely everything," he said, according to the BBC.

But Breivik showed no remorse for the slayings, saying that his rampage was "necessary".

The 33-year-old killed eight people after denoting a bomb near government offices in Oslo before travelling to a Labour party political camp on Utoya island and shooting dead 69 people, including many children.

Since the massacre Breivik said he had been shunned by family and friends, and said that his pain was the same of those whose loved ones were slain.

"The only difference was that for my part it was a choice," he said.

Denying he was insane, Breivik said he had been the victim of "racisim".

"Because I am a militant nationalist, I am being subjected to grave racism," he said. "They are trying to delegitimise everything I stand for."

The right-wing extremist also apologised to the family of a pub landlord who was injured in the bomb attack, saying he didn't mean to hurt "civilians".

But asked if he wished to apologise to the families of those killed on Utoya, Breivik declined.

"Utoya is a political indoctrination camp," he said.

In his evidence Breivik also said that he thought political leaders in Norway would have ordered his execution once he was arrested, and that his family might also be killed.

He also gave no comment on the supposed "Knights Templar" organisation he has described in his testimony, but which the prosecution believes might not exist.

Breivik also compared himself to Al Qaeda, as he has done previously, saying that "nationalists have a lot to learn".

The killer left relatives and friends of those slain in tears on Friday, after 90 minutes of devastating testimony in which he calmly described the shootings on Utoya in exacting detail.

He could face 21 years in prison if the court decides he is sane, possibly much longer if he is considered a public danger.