Russia’s state communications watchdog said on Wednesday it was restricting the use of Twitter by slowing down its speed, accusing the social media platform of repeatedly failing to remove banned content from its site.

Axar.az reports citing foreign media that Roskomnadzor threatened to block the service completely and said there were more than 3,000 posts containing illegal content on it as of Wednesday.

Twitter, like other U.S. social media, is used widely inside Russia by allies of Kremlin critic Alexei Navalny whose jailing last month prompted nationwide protests.

“The slowing down will be applied on 100% of mobile devices and on 50% of non-mobile devices,” the regulator said in a statement on its website.