The founder and CEO of the popular encrypted messaging service Telegram was detained at a Paris airport, French media reported Sunday.

Pavel Durov was detained at the Paris Le Bourget airport on Saturday evening after landing in France from Azerbaijan, according to broadcasters LCI and TF1.

Investigators from the National Anti-Fraud Office, attached to the French customs department, notified Durov that he was being placed in police custody, the broadcasters said.

French prosecutors declined to comment on Durov's arrest when contacted by The Associated Press on Sunday, in line with regulations during an ongoing investigation.

French media reported that Durov, 39, was the subject of an arrest warrant issued by France based on allegations that his encrypted platform has been used for money laundering, drug trafficking and allowing the sharing of content linked to sexual exploitation of minors.

Western governments have often criticized Telegram for lack of content moderating on the messaging service.

Russian government officials expressed outrage at Durov’s arrest, with some highlighting what they said was the West's double standards on freedom of speech.

“In 2018, a group of 26 NGOs, including Human Rights Watch, Amnesty International, Freedom House, Reporters Without Borders, the Committee to Protect Journalists, and others, condemned the Russian court’s decision to block Telegram,” said Maria Zakharova, spokesperson for Russia’s Ministry of Foreign Affairs.

“Do you think this time they’ll appeal to Paris and demand Durov’s release?” Zakharova said in a post on her personal Telegram account.