The Russian government Thursday demanded social media companies continue removing posts encouraging minors to protest the detention of political leader Alexei Navalny.

The statement issued by Roskomnadzor, the state’s media watchdog, declared that social media companies had been put on notice to prohibit certain content. Though, the agency also commended restrictions during last week’s protests, as they “significantly [reduced] the number of underage participants and [prevented] the appearance of victims among them.”

In a statement to AFP, Facebook denied that any content had been restricted. TikTok did not respond to the NYT for comment.

If found in violation of the government’s demands, the social media companies could face penalties of up to four million rubles (over $52,000). The agency cites Article 13.14 of the Administrative Code of the Russian Federation as a basis for the fine, which prohibits “disclosing information, to which access is limited by federal law.”

The Russian government’s threats come as Navalny’s supporters continue to push back against his recent detention. Many have resorted to online platforms to spread information about protests. For example, one user’s TikTok post went viral after encouraging protesters to impersonate being an American to avoid arrest.

The international community has signaled strong support for the Russian opposition leader. The UN Human Rights office called for his release and respect for due process. US President Joe Biden personally requested Navalny’s release in a phone call to Russian President Vladimir Putin.

Navalny supporters are attempting to organize more protests for Sunday.