MOSCOW, Russia (AFP)—Russia on Thursday added Telegram founder Pavel Durov to a blacklist of “terrorists and extremists”, a day after saying it was seeking his arrest over accusations he let his platform be used by Ukrainian intelligence.

The serial tech founder, who has lived outside Russia for years and holds French and United Arab Emirates passports, has frequently clashed with the Russian authorities as Moscow has tightened its grip on the internet.

His Telegram messenger is one of the country’s main communications platforms. Officials have repeatedly tried to block access or thwart its success in a bid to pressure Durov to hand over user data, or push Russians to use an unencrypted state-backed alternative.