Russia has accused Twitter of "maliciously violating" its laws by failing to remove banned content from its platform.
The social network has failed to take down more than 2,500 banned posts in the last four years, according to the country's communications watchdog, Roskomnadzor.
Twitter was also accused of ignoring more than 28,000 requests from Russian authorities to take action.
"Since 2017, Twitter has not deleted 2862 materials with prohibited information," Roskomnadzor said in a statement on Monday.
This included 2,336 posts and content related to forms of suicide and incitement to suicide, the authority added.
Moreover, the regulator cited 352 pieces of content featuring "pornographic images of minors" and 174 posts related to the production and use of drugs.
"In total, Roskomnadzor sent more than 28,000 removal requests to Twitter with regard to information recognised as prohibited," the statement added.
Social networks and owners of online platforms can be fined under Russian law for failing to delete illegal content and "prohibited information". These fines can be between 800,000 and 8 million roubles (€8,957 and €89,568).
In the case of a second violation, Roskomnadzor says that fines can be increased to one-fifth of the company's total annual revenue.
Euronews has contacted Twitter for a statement in response to the watchdog. The tech giant has previously been fined small amounts for breaching Russia's data laws.
In recent months, Moscow has stepped up efforts to control foreign social media platforms, especially in the wake of opposition demonstrations for the release of Alexei Navalny.
While allies of the Kremlin critic have used social media to call on Russian citizens to rally across the country, Russia's Foreign Ministry has accused platforms of failing to take action on calls for "illegal" protests.
"We ask the management of Internet platforms to refrain from disseminating calls for participation in unauthorised public events," Roskomnadzor said in a statement last month.
In December, Russia's lower house of Parliament passed a new law that could also restrict access to social networks in the country if they "discriminate" against Russian media.
Earlier this month Twitter said it had removed 100 accounts for "conducting pro-Russian propaganda" and "undermining confidence in the stability of the NATO alliance".
In response, Roskomnadzor sent a letter to Twitter executives, asking for an explanation for the action.