Iranian state TV says government bodies have been barred from using foreign messaging apps.
State TV says Wednesday the ban was imposed by the Presidential Office on all public institutions. It was not clear if the ban applied to civil servants outside of work hours. The report did not elaborate on penalties for violating the ban.
The Telegram app is used by an estimated 40 million Iranians, and was used to organize anti-government protests in December and January.
Last month, officials said Iran would block Telegram for reasons of national security in response to the protests, in which at least 25 people were killed and nearly 5,000 reportedly arrested.
Telegram was temporarily shut down during the protests, but many continued to access it through proxies and VPN services.