The self-confessed Norwegian killer Anders Behring Breivik told police he had several targets in mind when quizzed after the attacks that killed 77 people, a police prosecutor said on Saturday.
Norwegian media reported that the right-wing extremist, who admitted to the July 22 shooting on an island summer camp and a car-bomb blast in Oslo earlier the same day, also wanted to hit the royal palace and the ruling party headquarters.
"During his interrogations he said in general terms that he was interested in other targets," prosecutor Paal-Fredrik Hjort Kraby told a press briefing.
"They were targets which would seem natural for a terrorist," he said, declining to give details.
According to the Verdens Gang tabloid, the royal palace was a target because of its symbolic value.
The Labour party headquarters were targeted, the paper said, because of the party's role in creating the multi-cultural society so loathed by Behring Breivik.
The tabloid, which did not reveal its source, also said investigators believed Behring Breivik had trouble making explosives beyond those that killed eight people in the Oslo blast, which targeted government offices.
Another 69 people, mainly young, were killed in the shooting spree at a Labour Party summer camp on the island of Utoeya.
Behring Breivik, 32, believed he was engaged in a struggle to defend Europe against an Islamic invasion and despised anyone who believed in democracy, his lawyer, Geir Lippestad, has previously told the media.
Lippestad also told a newspaper on Friday that his client had planned to attack other targets.
"There were several projects of different scale for that Friday," Geir Lippestad was quoted as telling Aftenposten.
"Things happened that day, which I don't want to go into (here), which meant events unfolded differently from what he had planned," Lippestad added.
Norwegian police refused to identify other potential targets. However, one of the lead investigators, John Frederiksen, said: "What we can say on an operational level is that with the information obtained in the initial phase of our enquiries and from the elements published (by Behring Breivik), we have inspected a dozen sites to see if there was any kind of threat.
"We have not found anything" to back that up, he added.
In a report published late on Friday, Norway's police intelligence unit, the PST, concluded there was no cause to raise the threat level in the country, given the "unique" nature of the July 22 attacks.
"Based on several factors, it is unlikely that the attacks will be followed by further similar terrorist attacks," the intelligence service said.
"In all likelihood, the perpetrator planned and executed these actions without support," the report said.
Behring Breivik said in a 1,500-page manifesto published online just before the carnage, which doubled as a manual for would-be followers, that "12 failed attempts on an extremely well-protected individual could have alternatively been 12 successful attacks on lesser targets, executing more than 50 primary targets."
Psychiatrists are now assessing whether he is legally insane, as prosecutors seek to bring him to trial next year. The psychiatrists are due to provide their assessments by November 1.
Norway, still shaken by the carnage, began burying the 77 victims on Friday.