Norwegian Prime Minister Jens Stoltenberg has said his country will "not be intimidated or threatened" by Friday's bomb and gun attacks.
He said the violence had been designed to spread panic, but Norwegians would "stand firm in defending our values".
Later Mr Stoltenberg announced he was setting up a "22 July Commission" to investigate the attacks.
Anders Behring Breivik, a far-right extremist, admits carrying out the attacks which left at least 76 dead.
The bomb in the capital Oslo targeted buildings connected to Norway's Labour government, while the mass shooting occurred at an annual Labour Party youth camp on a small island, Utoeya.
Mr Breivik has said he had wanted to inflict maximum damage on the party, which he accuses of failing the country on immigration, according to his lawyer.
A search is continuing for victims, with two police vessels combing the waters of the lake around Utoeya. Local police said "a number of personal belongings" had been found at the bottom of the lake.
Speaking at a news conference at his residence, Mr Stoltenberg said the new commission, which would be independent and had been agreed with all Norway's political parties, would analyse everything that had happened on Friday.
"We need to learn any lessons from this," he said.
Earlier Mr Stoltenberg said the attacks were directed at Norway's "fundamental values" - democracy and openness - and that the response would be "more democracy, more openness". He said he expected people to participate more broadly in politics.
He added it was too early to consider new security laws.
"Now is the time for comfort for those who have lost family members [and] friends, and to help those who are still wounded," he said.
"Then afterwards, and especially after the investigation is finished, there will be a time for going through all the experiences, learning from what happened and then draw the conclusions regarding, for instance, security measures."
But the prime minister said the time would come when it was necessary to move on.
"We have to, at some stage, move back to some kind of normality, and also to convey the message of sadness with a message of something positive - and that is that we have seen a very united Norwegian people."
Speaking English throughout the news conference, Mr Stoltenberg expressed thanks for the deep solidarity "from all corners of the world".
Meanwhile the leader of the police squad who apprehended Mr Breivik on the island said it was a "completely normal arrest", and suggested the gunman had surrendered readily.
Haarvard Gaasbakk said that police had yelled to the gunman to surrender and, in limited visibility, he suddenly appeared before them with his hands in the air and his weapon 15m away on the ground.
Victims being named
The authorities have said they believe Mr Breivik acted alone.
Norwegian domestic intelligence chief Janne Kristiansen said no evidence had so far been found linking Anders Behring Breivik with far-right extremists in Norway or elsewhere.
"We don't have indications that he has been part of a broader movement or that he has been in connection with other cells or that there are other cells," she told the BBC.
But she added that the possible existence of accomplices was still being investigated. "We can't take any chance with this person," she said.
Friday's massacre prompted up to a quarter of a million people to take to the streets of Oslo on Monday to commemorate the victims.
The names and addresses of the first four confirmed victims were published on Tuesday on the Norwegian police website.
Police chief Sveinung Sponheim said names would continue to be released at 1800 local time (1600 GMT) each day until all the victims had been identified and all relatives informed.
Meanwhile AFP news agency quoted a police union spokesman as saying 20m Norwegian kroner (2.6m euros; £2.3m) would be released to create 100 new police jobs in areas affected by the attacks.
Mr Breivik is facing terrorism charges and police are considering also charging him with crimes against humanity, which carry a possible 30-year sentence, a prosecutor has said.
He appeared in court on Monday to face charges of destabilising vital functions of society, including government, and causing serious fear in the population.
He accepted responsibility for the attacks but denied the terrorism charges, and was remanded in custody for eight weeks, the first four in full isolation and on suicide watch.