A secret Facebook group of Swedish jihadists and their supporters was accessed by the Swedish broadcaster SVT on Wednesday, with the network discovering messages praising the attack on Charlie Hebdo's offices in Paris.
One member of the group posted: "Now these disgusting pigs will think twice before they mock Allah and His prophet."
Another called for Allah to "multiply such attacks".
Those accessing the site were understood to include jihadists who had been involved in fighting in Syria and Iraq. 430 people are members of the Facebook group, which is invisible to the public.
At a Stockholm rally
in solidarity with the victims of the shootings on Wednesday, a French student told The Local that he had also seen Muslims praising the attacks online.
“It is a very complicated situation and we should not just ‘amalgamate’ all Muslims and extremists, because most Muslim people are not extreme,” said Lucas Bayle.
"But it is the case that some Muslims agree with what happened. I have seen this on social media and on Facebook – people saying it was their fault [the magazine]…I think that there is a big problem with this kind of mentality.”
LIVE: The Local France reports on the Paris shootings
Muslim leaders worldwide have criticized the attacks.
France's Muslim Council (CFCM) described the shootings which left twelve people dead as "barbaric".
Sweden's Islamic Association posted a statement on its website saying that the attack went "against everything that Islam stands for".
"We want to express our sincere sympathy and support to the victims' families and the whole French population," it added.
The organization also urged Muslims in Sweden to "be cautious" of an increased risk of anti-Muslim hate crimes.
On Thursday it emerged that a mosque in Mariestad in southern Sweden had been vandalized with graffiti, including the comment "go home", although it was unclear whether this took place before or after the Paris shootings.
Mohammed Fazlhashemi, Professor of Islamic theology and philosophy at Sweden's Uppsala University told The Local
on Thursday that "counter attacks" following the Paris shooting were likely and said that many Muslims in Sweden now feared for their safety: "We've seen Islamophobic rhetoric gradually strengthening in Swedish society…we may see reprisals in Sweden".
"Islamophobia has been around for a long time, but when political parties get a voice, then we really see the effects… After what's happened in Paris, the Swedish government has to show that this is totally unacceptable."