"Sweden has had a privileged position in the international intelligence system since the 1940s due to its exceptionally high signals intelligence competence," Wilhelm Agrell, professor of intelligence analysis at Lund University, told the Dagens Nyheter (DN) newspaper.
The comments made on Friday come after remarks made by investigative journalist Duncan Campbell on Thursday in front of a European Parliament committee that Sweden was one of the United States' most important partners in efforts to monitor internet communications across the globe.
"A new organization has joined the "Five Eyes" and is seen as the largest cooperating partner to [the UK's] GCHQ outside the English-speaking countries – and that is Sweden," Campbell can be seen telling the committee in a video of the hearing, referring to the colloquial term used to refer to the US, UK, New Zealand, Australia, and Canada.
Specifically, he pointed to the Swedish National Defence Radio Establishment (Försvarets radioanstalt, FRA), explaining that the agency helped the US National Security Agency (NSA) and British GCHQ gain access to signals intelligence carried through fibre optic cables at the bottom of the Baltic Sea.
According to Agrell, Sweden sits in a geo-strategically important position with respect to the international signals intelligence system by having the ability to access cables that carry data traffic between the east and west.
"Sweden sits on a pipeline filled with golden eggs," he told DN.
Speaking with the TT news agency, Agrell explained that it's not against the law for Sweden to provide the US and UK with access to the cables as such actions weren't prohibited in the controversial 2009 FRA-law that regulates the agency's intelligence gathering activities.
"The Swedish debate about the FRA-law was about the privacy of Swedish citizens. International cooperation wasn't discussed. But there is backdoor in the FRA law; when it comes to international cooperation, more or less anything goes," he said.
He added that it's improbable that the Swedish government is unaware of the intelligence sharing.
"The government should know about this. I heard Carl Bidlt wavering when he was asked about it, but he can't waver," Agrell said.
When asked about whether Sweden gave the United States access to the Baltic Sea cables, Prime Minister Fredrik Reinfeldt avoiding confirming or denying the activities.
"I'm not confirming anything, other than to say that Sweden, for a long time, throughout the post-war period, has cooperated with other countries and that we have a national security policy doctrine that says we should," he told TT.
Some have criticized Reinfeldt for not pressing US President Barack Obama on NSA intelligence operations detailed in leaks by whistleblower Edward Snowden, documents to which Campbell referred in his presentation to the European Parliament on Thursday.
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But Agrell said it was unfair to expect Reinfeldt to "put Obama up against the wall" over the issue.
"If you have both your hands in the cookie jar, you're not going to be especially convincing," he told DN.