In its annual report, the agency said the threats posed by Russia have widened over the past year, ranging from online trolls and disinformation campaigns to efforts to demonize Swedish politicians and authorities.
The new report confirms that Sweden asked a Russian embassy official to leave the country last year and that Säpo believes at least 10 Russian diplomats working in Sweden are, in fact, spies.
"It is very well coordinated by the Russian side," said Wilhelm Unge, who works with counterespionage at Säpo.
There are likely more than 10 spies, said Joakim von Braun, a freelance journalist specializing in Soviet and Russian intelligence, speaking with Radio Sweden. He said Russia's espionage efforts have been singled out by Säpo reports for the last three years. But this year's report emphasized the rise in propaganda activities.
"Much of it involves either totally fabricated news or disinformation when you take a real piece of information and twist it to your own political purposes. The Russians have always mastered that kind of disinformation warfare. And they've been doing that since the 1920s," said von Braun.
Säpo's 2014 annual report claimed Russian spying was extensive and had been on the rise since the Ukraine crisis.
At least 300 Swedes have gone to fight in Syria and Iraq for the Islamic State, Säpo states in its new report. Of these, 135 have returned while 44 have died.
The militant group's propaganda aimed at young people has reached an unprecedented scale in Sweden, according to Säpo, but fighters returning from IS are the most dangerous to the nation.
Sweden's massive influx of refugees in 2015 has also affected Säpo's work. The security group now has closer ties with the Swedish Migration Agency and has seen the number of cases referred to it skyrocket, according Malin Fylkner, principal security analyst.