By Jorn Madslien BBC News
Assistant Chief Constable Egil Vrekke: "There are a lot of casualties"
July 2011 Last updated at 16:57 GMT
If the bomb blast in Oslo turns out to be a terror attack, it will mark a 9/11 moment for Norway.
Like the US before the attacks in New York and Washington a decade ago, Norway has never previously been subjected to serious terrorist attacks.
This is not because the country has been particularly good at protecting itself; rather, it is because it has stayed away from international conflict.
Though a long-standing Nato member, Norway has only recently increased its involvement in military missions in countries such as Afghanistan or Libya.
Consequently, its foreign policy has not made the country many enemies, with Norwegian diplomats often citing the country's commercial whaling as the most controversial issue they have to deal with.
Norway is an incredibly open society.
The Royal Family is free to move about with limited security, both in the nation's relatively small and peaceful cities, as well as on holiday in the mountains or on the coast.
The country's politicians and business leaders mix freely with ordinary people in a manner rarely seen elsewhere in the world.
Few people have secret addresses and telephone numbers - open the phonebook online and you will find links not only to aerial shots of people's houses and maps of where they live, but also details about their email addresses and their place of work.
This is a society where top politicians, business executives and other celebrities often include their private telephone numbers and home addresses on their business cards.
Even their salaries and the size of their fortunes are made public by the tax authorities once a year, only to be plastered all over the newspapers.
Local newspapers do the same with small-town politicians, local shopkeepers and amateur sports people. The public is free to use the taxman's online search engine to snoop on friends and neighbours' financial affairs.
The post, which in the UK tends to be shoved through the front door, is normally placed in unlocked post boxes outside people's homes, making it easy for anyone with criminal intent to intercept anything from bank statements to medical records.
To the outside world, the lives lived by Norway's people, both the elite and ordinary folk, may seem naive.
Though up to now they have not seen any reason to protect themselves.
Like Sweden before the murder of Prime Minister Olof Palme in 1986, the Norwegian people have collectively resisted any calls for greater home security.
To them, living in an open society has been not just a privilege, but also a statement to the rest of the world; a display of how it is possible to live together in peace.
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Such feelings were voiced after the Norwegian publisher of Salman Rushdie's The Satanic Verses, William Nygaard, was shot and wounded outside his home in Oslo in 1993, two months after Ayatollah Khamenei issued the fatwa.
At the time, the political and intellectual elite stressed the importance of resisting the temptation to respond to the fear as it quickly spread through the population by raising the barriers and increasing the intolerance of those from the world outside.
They may well do so again now, though this time might be different.
Norway's attitude to risk might now change, quickly and dramatically, as private individuals withdraw and as central authorities bolster security.
If so, a possible goal of the attackers may well have been achieved, in that they have robbed Norway of its innocence.