Pavel Durov, the billionaire founder of encrypted messaging app Telegram, has been arrested in France, according to local reports.
The 39-year-old tech chief was reportedly detained after his private jet landed at Le Bourget airport on the outskirts of Paris.
News broadcasters BFMTV and TF1 have quoted unnamed sources as saying the Russian-born entrepreneur – who became a French citizen in 2021 – was the subject of a search warrant.
Both outlets suggest the investigation was focused on a lack of moderators on Telegram and potential criminal activity by users.
Neither French police, the Interior Ministry, nor Telegram have commented on those claims.
Telegram is one of the most downloaded apps in the world, with predictions it will achieve close to one billion users within a year.
It offers end-to-end encryption – effectively protecting data from being intercepted – and has a strong focus on privacy.
Telegram is particularly influential in Russia, Ukraine and the republics of the former Soviet Union.
This focus makes the app popular with pro-democracy movements and other protesters in countries with strict laws.
It has become a critical source of information on Russia’s war in Ukraine, and is used heavily by both Moscow and Kyiv officials.
It is ranked as one of the major social media platforms and claims to have more than 950 million monthly active users.
But it has also been used for criminal activity and recently by far-right activists who sparked riots in the UK over the Southport stabbings.
It is unclear what Mr Durov was arrested for but BFMTV reported the warrant concerned the app’s possible use in money laundering, drug trafficking or sharing of child sex abuse content.
The app’s founder, owner and chief executive left Russia in 2014 after losing control of his previous social media company Vkontakte (VK).
He refused to comply with government demands to shut down opposition groups on the platform and would not hand over data on Ukrainian protesters to security agencies.
Meanwhile Russia’s Foreign Ministry said it was taking steps to “clarify” whether he had been arrested.
Mr Durov was naturalised as French in August 2021 and is also a citizen of the United Arab Emirates.
Writing on X, US commentator Tucker Carlson believes Mr Durov has been detained in France because of his refusal to “censor the truth”.
In an interview with the American TV personality in April, Mr Durov said he was determined to keep Telegram “neutral” and “free from geopolitics”.