Former Swedish ambassador to Washington Rolf Ekéus said he feared WikiLeaks' publication of confidential diplomatic correspondence could result in fewer contacts being willing to provide diplomats with vital information.
"Diplomats don't write memoirs. It may matter who provides information to diplomats. If they know they may be published to critique, they may dry up. It's sad for those who are exposed, who were trusting, to keep up a dialogue between countries, it's not good at all," Ekéus told The Local on Monday.
He added, however, that he didn't expect the release of the documents to seriously damage Swedish-American relations.
The documents, many of which cover the Swedish presidency of the European Union in 2009, include observations that Sweden was the leader of a handfull of European countries to oppose sanctions on Iran at a meeting in Brussels in 2009.
Swedish newspaper Expressen, which has reviewed many of the documents, also revealed that the US Embassy in Stockholm sent detailed reports to Washington on late foreign minister Anna Lindh, outlining her criticism of the American war on terror.
Sweden only features in any meaningful way in 819 of the 250,000 documents obtained from the US SIPRNet intelligence database. Of these, about 671 were sent by the US Embassy in Stockholm.
Swedish Foreign Minister Carl Bildt was warned by US diplomats that documents concerning Sweden could be released in the leak. Writing on his blog on Monday morning, Bildt said the publication would have negative consequences well beyond the US State Department.
"The intention behind this publication cannot have been anything other than to damage American diplomacy, although the effect with really be to damage diplomacy in general," he wrote.
Bildt's press spokeswoman Anna Charlotta Johansson told The Local that Bildt would not make any more comments on WikiLeaks on Monday.
Former Swedish foreign minister and Ekéus' successor as Sweden's ambassador in Washington Jan Eliasson also warned that the leak could negatively affect the conduct of diplomacy.
"It's hard to preserve the trust needed within diplomacy when you know that confidential conversations risk coming out. It's going to affect the quality of the reporting," Eliasson told the Dagens Nyheter (DN) newspaper.
"Diplomacy shouldn't be vague and focused on gossip, but rather clear and graspable – like cold water, as I usually say. That type of reporting is what one expects."
Ekéus called the latest WikiLeaks disclosures "regrettable," but revealed his ambivalence about the organisation on the whole.
"It is too early to make a judgment. I was relatively positive about the initial disclosures of warfare, the fact that there was suffering and that mistakes led to serious attacks. This is terrible and it is important that they publish them, I congratulate them," he said.
"But on diplomacy, this is about keeping peace. I don't see the common value in that, but the common harm. It is one thing about what is in the findings. It's another thing that it's a leak," Ekéus added.
He was the director of the UN Special Commission on Iraq from 1991 to 1997, which served was the UN disarmanent observers in Iraq after the Gulf War, and has also chaired the Stockholm International Peace Research Institute.
"It's one thing to kill and carry out warfare, it has to do with the past. You talk diplomacy, to solve problems, work to avoid violence," said Ekéus.
Regarding the contents of the new documents, he said there were no major revelations, but was surprised that highly confidential diplomatic correspondence was exposed.
Nevertheless, Ekéus felt that bilateral relations between Sweden and the United States would weather any storm caused by the documents.
"I don't know if relations will be seriously damaged. There can be details that are irritating, but diplomats have the freedom to make their judgments, they have the privilege and right to make their assessments. I must be able to trust using diplomacy as a tool," he said.
Ekéus added that Sweden has managed with close to 200 years of peace as a result of successful solutions through diplomatic negotiations.
Particular matters of interest to him were new details about the Koreas, Middle East and EU, as well as judgments on Russia and world leaders that have not been previously reported.
To Ekéus, the most surprising revelations in the documents were the "great nervousness" expressed about the Iranian nuclear programme and whether it is moving towards manufacturing weapons.
"It probably shouldn't surprise you either, but it is how the concern is expressed," he said.