“Russian public diplomacy measures such as Sputnik have gained in importance over the course of the last few years, so we wanted to study its dominant narratives and how they shifted over time,” report co-author Sebastian Asberg told The Huffington Post via email.

After taking a closer look, he said researchers determined that Russia’s influence tactics “went beyond these traditional public diplomacy measures.”

A forged letter purportedly written by Sweden’s foreign affairs minister about seeking cooperation with the self-described Islamic State militant group was among the most egregious findings, he added.

Russia has not yet commented on the allegations, but Swedish prime minister Stefan Löfven said Monday that he “cannot rule out” that Russia could try to influence Sweden’s elections, The Local reports.

Russia’s reported focus on Sweden isn’t surprising, according to Asberg.

“The Baltic Sea region is of increasing geostrategic importance to Russia,” he said. “This is mainly due to the Baltic States’ membership in NATO, which would make it a likely scene of any potential conflict between Russia and NATO. Russia therefore wants to minimize NATO’s presence in the region.”