Key digital rights activists – including Edward Snowden and hacker Jacob Appelbaum – have been blacklisted from the Stockholm Internet Forum (SIF) on internet openness and freedom. The move has caused a stir at the gathering and outraged Twitter users.

The third annual European meeting of internet activists kicked off in Sweden on May 26, with its main theme being “Internet– privacy, transparency, surveillance and control.”

But strangely enough, those whose names immediately spring to mind when it comes to the issue of surveillance were not allowed to attend the event.

Former CIA employee Edward Snowden, who revealed the NSA's mass spying program, was not invited. Neither was journalist Glenn Greenwald, who broke the story.

Hacker Jacob Appelbaum, who found German Chancellor Angela Merkel’s mobile phone number in Snowden’s database, didn't receive an invitation either.

I have been silenced this year from attending #SIF14 in person as have others. This is the result of speaking out against mass surveillance. — Jacob Appelbaum (@ioerror) May 26, 2014

The conference also failed to invite representatives of WikiLeaks, which repeatedly made headlines worldwide by leaking diplomatic cables.

According to German magazine Cicero Online, the only non-governmental organization among the hosts of the conference – .SE – had made a list of possible candidates and sent it to the Ministry of Foreign Affairs for approval.The ministry vetoed the activists from attending the SIF – the brainchild of Foreign Minister Carl Bildt. Snowden’s name was marked red, the magazine wrote, suggesting that could be code for “do not invite.”

When asked to comment on the matter, the ministry stated that the conference’s main focus was to “represent a wide array of backgrounds, cultures and opinions.” It added that a key ambition was to have an equal number of male and female invitees and that at least a half of them had to be from developing countries. “We would also like to point out that those who haven’t been invited are able to follow the entire conference online and give opinions and raise questions during the discussions,” the ministry said, as quoted by Cicero.

The decision to snub Snowden and other activists from the meeting sparked a wave of criticism among forum participants, while Twitter exploded with a stream of outrage and sarcastic comments under the hashtag #SIF14.

Swedish Ambassador Olof Ehrenkrona acknowledged on Twitter that the ministry rejected .SE’s proposal to invite Snowden.

“Not a boycott. We just did not invite him. Others not invited are not boycotted,” he tweeted, triggering a heated conversation which involved both Appelbaum and Petra Sorge (the author of the article on Cicero).

Sad to see people like #Snowden & @ioerror not invited to #SIF14. At this crucial juncture, they're inspiration for people all over world — Anja Kovacs (@anjakovacs) May 27, 2014

Number 1 question asked to me tonight at the #sif14 official reception: What do you think about Snowden being blacklisted? #InternetFreedom — Onnik J. Krikorian (@onewmphoto) May 26, 2014

For #SIF14 organisers to use argument that developing countries were prioritised, to justify the non-invitation of #Snowden is distasteful. — Jane Duncan (@DuncanJane) May 26, 2014

Congratulations to Swedish Foreign Ministry for making Sweden a laughing stock. #snowden et al #SIF14 — roppert (@roppert) May 27, 2014