Russia has imposed new fines on Facebook, Twitter, and Telegram for failing to remove banned content.
The three social networks were all sanctioned by Russia's judiciary on Tuesday, days before the country's parliamentary elections.
The Moscow court fined US giants Facebook and Twitter 21 million and five million rubles (€244,000 and €58,000 respectively).
Meanwhile, the Russian-founded messaging service Telegram was fined nine million rubles (€104,000).
While exact details of the case were not made clear, big tech companies have previously been cited for not removing online publications that promote drugs, pornography, or suicide.
In March, Twitter's speed was slowed in Russia due to its failure to comply with requests to delete the illegal posts.
The fines represent the latest tensions between the Kremlin and major foreign social networks in recent months.
Moscow has accused the social networks of not properly moderating their content and, in some cases, of interfering in Russian affairs by refusing to delete publications by the Kremlin's opposition.
Earlier this year, Russia had also fined companies for not removing posts that encouraged young people to rally in support of the jailed opposition leader Alexei Navalny.
Last week the country's state communications regulator blocked Navalny's "Smart Voting" website and urged both Google and Apple to also remove the app from their stores.
Navalny, who is serving two and a half years in prison, has sued the regulator and the prosecutor's office over the decision.
Russian President Vladimir Putin has assured that Moscow would not block foreign social networks but has warned the companies that they must comply strictly with the country's laws.
In December, Russia's parliament approved a bill that allows the country to restrict access to US social media companies if they are deemed to discriminate against Russian media.
Kremlin spokesman Dmitry Peskov this week acknowledged the risks of foreign interference in this week's elections.
Last Friday, Russia's foreign ministry summoned US ambassador John Sullivan over alleged interference by US tech giants in the country's internal affairs.
Sullivan was received by Russian Deputy Foreign Minister Sergey Riabkov, who assured him that Moscow "has irrefutable evidence that US digital giants are violating Russian law".