Russian state communications watchdog Roskomnadzor said tech giants Google and Facebook had allowed political advertising during Sunday's regional elections despite being asked to ban such publicity.
"Such actions can be seen as interference in Russia's sovereign affairs and hindering the conduct of democratic elections in the Russian Federation", the watchdog said on its website.
Reuters was not able to immediately reach Google or Facebook for comments.
Russia is holding regional elections on Sunday, including in Moscow, after the exclusion of many opposition candidates triggered big protests in the Russian capital over the past several weeks.
Roskomnadzor said on Friday it asked Facebook and Google to ban the publication of political advertising during elections on Sunday and on the preceding day, in line with Russian law.
