Telegram CEO Pavel Durov has been arrested by French police at Le Bourget Airport near Paris. The 39-year-old billionaire was detained upon landing, reportedly under a warrant related to Telegram’s moderation practices. Authorities accuse Durov of failing to curb criminal activities on the popular messaging app.

Durov, who holds dual citizenship in the UAE and France, is known for founding Telegram in 2013 and previously leaving Russia after resisting government demands to censor opposition groups on his VKontakte platform.

The Russian Embassy in France has requested clarification from French authorities and is seeking consular access to Durov. Russian officials have condemned the arrest, while Elon Musk has voiced his support for Durov on social media.

Telegram, popular in Russia, Ukraine, and former Soviet states, has faced criticism for enabling the spread of misinformation and harmful content due to its large, unmoderated groups.