Anders Behring Breivik was questioned for 10 hours on Friday to verify details from previous sessions and answer new points.
Police would not confirm reports that he had also wanted to attack the palace and Labour Party headquarters.
Funerals have begun for the 77 people killed in the attacks.
Mr Breivik, an anti-Muslim extremist who blamed Labour for increased immigration, is believed to have single-handedly shot dead 69 people at a party summer camp on the island of Utoeya, hours after killing eight with a car bomb near government buildings in central Oslo.
The attacks on Friday 22 July traumatised Norway, one of the most politically stable and tolerant states in Europe.
'Several projects of different scale'Police lawyer Paal-Fredrik Hjort Kraby said the suspect had talked about other targets.
"In general, I would say that he had in his plans other targets but on this day it was only these two which were successful," he told reporters on Saturday.
Police lawyer Paal-Fredrik Hjort KrabyHe described Mr Breivik as "more than willing to co-operate... more than willing to explain himself".
Without citing its sources, Norwegian tabloid Verdens Gang reported that the suspect had considered attacking the royal palace because of its symbolic value, and Labour HQ because of his loathing for the party.
On Friday, Mr Breivik's lawyer, Geir Lippestad, told Aftenposten newspaper that his client had harboured "several projects of different scale for that Friday".
"Things happened that day, which I don't want to go into, which meant events unfolded differently from what he had planned," he added.
He said his client continued to show no remorse, saying the killings were "a necessary act... a war against the rule by Muslims".
Police are believed to have been checking targets identified by Mr Breivik in his manifesto, which outlines both his extremist ideas and details his preparations for attacks.
Huge demand for flowers Flowers cover the ground around Oslo cathedralSuch has been the demand for roses to mourn the victims nationwide, that the government has suspended duty on foreign imports of the flower until Tuesday.
A memorial concert at Oslo's cathedral on Saturday featured the Norwegian Broadcasting Corporation Symphony Orchestra and some of Norway's best-known recording artists.
Families of the victims, rescue personnel and health personnel were invited to the concert, which Crown Prince Haakon and his aunt Princess Astrid also attended.
Friday saw the first two funerals: of 18-year-old Bano Rashid, who was buried near Oslo, and of Ismail Haji Ahmed, 19, in the south-western town of Hamar.
Foreign Minister Jonas Gahr Stoere travelled to the Nesodden peninsula to attend the funeral of Ms Rashid, a Kurdish immigrant from Iraq.
Both victims were killed on Utoeya, where young members of the Labour Party had been attending an annual summer camp.
Memorial ceremonies were also held in churches and mosques and at non-religious gatherings around the country.
Norway plans to set up an independent "July 22 Commission" to examine the attacks, including investigating whether police reacted too slowly to the shootings at Utoeya.
A court has appointed two psychiatrists to try to examine Mr Breivik's actions, with a mandate to report back by 1 November. His lawyer has said he is probably insane.