The IISS, one of the most respected think tanks in the world, claims there's never been any doubt that the invasion of Iraq led to increased recruiting by al-Qaida and further motivated its existing activists.
Norway's agreement to send troops after the invasion, albeit for so-called "humanitarian" work, also put it on al-Qaida's list of targets, according to the institute. The man believed to be the terror group's deputy leader, Abu Musab al-Zarqawi, has twice mentioned Norway as a probable terror target.
"We don't have any concrete intelligence to build on," Jonathan Stevenson of the IISS told Norwegian newspaper Dagbladet on Thursday. "But an overall evaluation of Norway's role in Iraq indicates that al-Qaida also has roots in Norway.
"It's also striking how many times the country has been mentioned as a possible terror target by the terror organization," Stevenson added.
Norway has a relatively large Muslim population, with the majority of immigrants since the 1970s coming from Pakistan. This prompted a local politician of Pakistani descent to urge members of the immigrant community to report any suspicions of terrorist activity.
Concern has also been raised over the ongoing presence in the country of Mullah Krekar, the controversial former head of suspected terror group Ansar-al-Islam. He came to Norway as a refugee in the early 1990s, but traveled back to northern Iraq several times to lead the guerrilla group and now is under a deportation threat.
IISS estimated that al-Qaida still has around 18,000 potential terrorists in its ranks, even though around half of the network's top leaders and around 2,000 of its recruits are believed to have been killed or captured in recent years.
