Telegram's founder and CEO Pavel Durov has returned to Dubai from France as French authorities continue to investigate alleged criminal activity on the popular messaging app, his Telegram channel announced on March 17.

Russian-born Durov, who holds French, Russian and Emirati citizenships, was arrested at an airport near Paris in August and faced preliminary charges related to crimes committed on the app, including drug trafficking, money laundering and distribution of child sexual abuse material. Durov has denied the charges.

French authorities had previously barred him from leaving France during the investigation, required him to pay €5mn ($5.4mn) for bail, and directed him to report to a police station twice weekly. These conditions have now been loosened to allow him to leave the country temporarily.

"As you may have heard, I've returned to Dubai after spending several months in France due to an investigation related to the activity of criminals on Telegram," Durov wrote in a post on the app. "The process is ongoing, but it feels great to be home."

Preliminary charges under French law indicate magistrates have strong reason to believe a crime was committed but allow more time for further investigation.

Durov said in his post that "when it comes to moderation, cooperation, and fighting crime, for years, Telegram not only met but exceeded its legal obligations."

Telegram was founded by Durov and his brother following the Kremlin's crackdown after mass pro-democracy protests in Moscow in 2011 and 2012.

The app serves as a popular news source in Ukraine, where media outlets and officials use it to share information about Russia's war and deliver missile and air raid alerts.

Western governments have frequently criticised Telegram for its lack of content moderation, which experts say makes the app vulnerable to use in criminal activity.