Norwegian gunman Anders Behring Breivik defended his massacre of 77 people, insisting Tuesday he would do it all again and calling his rampage the most "spectacular" attack by a nationalist militant since World War II.

Reading a prepared statement in court, the anti-Muslim extremist lashed out at Norwegian and European governments for embracing immigration and multiculturalism.

He claimed to be speaking as a commander of an "anti-communist" resistance movement and an anti-Islam militant group he called the Knights Templar. Prosecutors have said the group does not exist.

Maintaining he acted out of "goodness, not evil" to prevent a wider civil war, Breivik vowed, "I would have done it again."

Pressed by prosecutors later to explain what he meant, he compared his attacks to the U.S. atom bombs on Japan during World War II.

"They did it for something good. To prevent further war," Breivik said.

Breivik has five days to explain why he set off a bomb in Oslo's government district on July 22, killing eight people, and then gunned down 69 others at a Labor Party youth camp outside the Norwegian capital. He denies criminal guilt, saying he was acting in self-defense, and claims the targets were part of a conspiracy to "deconstruct" Norway's cultural identity.

"The attacks on July 22 were a preventive strike. I acted in self-defense on behalf of my people, my city, my country," he said as he finished his statement, in essence a summary of the 1,500-page manifesto he posted online before the attacks. "I therefore demand to be found innocent of the present charges."

He didn't express regret, but told prosecutors he would have preferred attacking a conference of Norwegian journalists instead of the Utoya youth camp, where most of the victims were teenagers.

"Unfortunately I wasn't able to carry out" an attack against that conference, he added.

Breivik's testimony was delayed after one of the five judges hearing the case was dismissed for his comments online the day after the attack that said Breivik deserves the death penalty. Lawyers on all sides had requested that lay judge Thomas Indreboe be taken off the trial, saying the comments violated his impartiality. He was replaced by backup lay judge Elisabeth Wisloeff.

Norway doesn't have the death penalty. If found mentally sane -- the key issue to be decided in the trial -- Breivik could face a maximum 21-year prison sentence or an alternate custody arrangement that would keep him locked up as long as he is considered a menace to society.

Breivik is being tried by a panel of two professional judges and three lay judges -- citizens appointed for four-year terms who participate on an equal basis in deciding guilt and sentencing. The system is designed to let ordinary people have a role in the Norwegian justice system, though the lead judge still runs the trial.

Again on Tuesday -- just like the start of his trial on Monday -- Breivik entered the court smirking before flashing a clenched-fist salute.

Judge Wenche Elisabeth Arntzen repeatedly interrupted Breivik on Tuesday, asking him to keep his statement short.

"It is critically important that I can explain the reason and the motive" for the massacre, Breivik replied.

According to Breivik, Western Europe was gradually taken over by "Marxists and multiculturalists" after World War II because it didn't have "anti-communist" leaders like U.S. Sen. Joseph McCarthy. The senator dominated the early 1950s with his sensational but unproven charges of Communist subversion in high government circles in the U.S. His probes gave rise to the term McCarthyism, which describes the persecution of innocent people on the charge of being Communists.

"But even McCarthy was too moderate," Breivik said.

Mette Yvonne Larsen, a lawyer representing victim's families, also interrupted Breivik, saying she was getting complaints from victims who were concerned that the defendant was turning the trial into a platform to profess his extremist views. Her remarks prompted the judge to again urge Breivik to wrap it up.

Breivik replied if he wasn't allowed to continue he might not speak at all.

He warned that Europe was heading toward a civil war between "nationalists and internationalists" and praised others suspected of right-wing extremist attacks in Europe. They included Peter Mangs, a Swede suspected of a string of shootings against immigrants in 2010 and three Germans -- Uwe Boehnhardt, Uwe Mundlos and Beate Zschaepe -- suspected in the killings of eight people of Turkish origin, a Greek man, and a policewoman between 2000 and 2007.

Asked why he started crying on Monday, when prosecutors showed an anti-Muslim film that Breivik posted on YouTube before the attacks, he said: "I was thinking about Norway and Europe, which are ruled by politicians and journalists killing our country. I was thinking that my country is dying."

On Monday, Breivik rejected the authority of the court, calling it a vehicle of the "multiculturalist" political parties in power in Norway. He confessed to the "acts" that caused the 77 deaths but pleaded not guilty.

Even his lawyers concede his defense is unlikely to succeed, and said the main thing for them was to convince the court that Breivik is not insane.

One official psychiatric examination found him legally insane while another reached the opposite conclusion. It is up to the panel to decide whether to send him to prison or compulsory psychiatric care.