The massacre on the island of Utøya is certain to lead to a security review, with particular stress on how Anders Behring Breivik obtained his weapons. Norway already has some of the toughest gun laws in the world, but they were apparently easily circumvented by the killer.

A licence is required to own a gun, and the owner must provide a written statement saying why he or she wants one. Many categories of guns, including automatics and some powerful handguns, are banned from sale altogether.

Hunting and outdoor sports are popular in Norway. But the laws are strict in these areas, too. Shotguns and rifles must be stored in a secure place, typically a specially designed gun safe, as must ammunition. Police have the right to inspect an owner's home to ensure the law is being followed.

Transporting a weapon to a public place is also covered by legislation. The owner must have a good reason for carrying a weapon, must ensure it is unloaded and concealed from view, but not worn on the body, and must keep the weapon under constant supervision.

Under the Firearm Weapons Act, only "sober and responsible" persons over the age of 18 may obtain a gun licence. For handguns, the age requirement is 21. In 2009, additional legislation was introduced, further tightening Norway's gun laws.

Perhaps because the laws are already so strict and gun crime is relatively rare, gun control is not generally considered a political issue in Norway, unlike countries such as the US where a citizen's right to bear arms is guaranteed by the constitution and fiercely defended.

American bloggers opposed to gun control were quick to note that Norway's regulations did not stop Breivik carrying out the attacks.

One poster, lawodevolution on democratic.underground.com, commented: "No full autos [automatics], license to own a gun, permission to transport, limit on how many you can own, need to show a reason to own a gun no carry, etc ... All this did not stop a guy from carrying a 'handgun, automatic, and a shotgun' at a no-gun zone in Norway.

"Gun control is a failure. These dirtbags do not obay [sic] laws and a person who wants to do a mass shooting will put the time and money into getting the equipment necessary to do the job ... When these idiots decide to attack they need to be shot in the crotch multiple times until their junk falls off."

Neighbouring Finland announced at the weekend that it was fast-forwarding tougher gun laws following the Norway attacks. The most recent changes in firearms legislation came into force at the beginning of June.

The new regulations make it more difficult to acquire handguns, and raise the minimum age for handgun ownership to 20. Applicants for gun permits are also required to undergo testing for their suitability.

The changes were influenced by two separate school shooting massacres in Finland, at Jokela in 2007 and Kauhajoki in 2008.