The attack hit the websites for newspapers Aftonbladet, Expressen, Dagens Nyheter, Svenska Dagbladet, Dagens Industri, Sydsvenskan and Helsingborgs Dagblad and lasted for an hour or longer.
Karin Olsson, Espressen's deputy editor-in-chief, tells Radio Sweden that the daily paper first noticed something was wrong about 8:20 pm.
"The news site was down and we noticed that our competitors Aftonbladet had great problems updating and giving access to its readers," Olsson says.
After an hour, Olsson says the paper was able to "manage" the attack and redirect the incoming traffic that was deliberately targeting the site. Olsson says that Expressen can only speculate why media outlets were singled out.
Shortly before the sites become inaccessible, an anonymous Twitter account alluded to the cyber attack against the media writing that "this is what happens when you spread false propaganda Aftonbladet.se #offline @Aftonbladet".
The account later tweeted "The following days attacks against the Swedish goverment (sic) and media spreading false propaganda will be targetted (sic)." and, as of Sunday morning, hasn't written anything since.
Police tell Swedish Radio News they are looking into the account and warned that more coordinated attacks could follow.
"We have had these kind of attacks before, but not so coordinated like this," Anders Ahlqvist, a cybercrime expert at the police's national operations department, told Swedish Radio News.
Ahlqvist said the so-called denial-of-service, or DDoS attack, original from the "east" but declined to specify to which country or region he was referring.
He added that just because the attack, which knocks websites offline by flooding them with too much traffic, came from computers in the east, that doesn't mean the individual or people organize the disruption are based there.
Websites for Swedish Radio were spared on Saturday night. Måns Nilsson with Swedish Radio's IT department, said he checked incoming web traffic when he first heard about a possible attack and saw an increase in visitors.
However, he believes the rise in traffic came from people looking for information about what was happening.