Ukraine has banned government and military officials from using the Telegram messaging app on state-issued devices because of concerns about Russian surveillance.

The National Security and Defence Council announced the restrictions on Friday after Kyrylo Budanov, head of Ukraine’s GUR military intelligence agency, presented the council with evidence of Russian special services’ ability to snoop on the platform, it said in a statement.

The ban was a “matter of national security”, it added.

Telegram is heavily used in both Ukraine and Russia and has become a critical source of information since  Russia launched its full-scale invasion of Ukraine in February 2022.

President Volodymyr Zelenskyy, who sits on the security council, as well as military commanders and regional and city officials, all regularly publish updates on the war and report important decisions on Telegram. Officials who use Telegram as part of their duties will not be affected by the new ban.

Based in Dubai, Telegram was founded by Russian-born Pavel Durov, who left Russia in 2014 after refusing to comply with demands to shut down opposition communities on his social media platform VKontakte, which he later sold.

Durov was arrested in France last month and charged with publishing illegal content on the platform.

The council statement said Budanov had provided evidence that Russian special services could access Telegram messages, including deleted ones, as well as users’ personal data.

“I have always supported and continue to support freedom of speech, but the issue of Telegram is not a matter of freedom of speech, it is a matter of national security,” Budanov said in his own statement.

After the decision was announced, Telegram issued a statement saying it had never disclosed anyone’s data or the contents of any message.

“Telegram has never provided any messaging data to any country, including Russia. Deleted messages are deleted forever and are technically impossible to recover,” Telegram said.

It said every instance of what it described as “leaked messages” had been proven to be “the result of a compromised device, whether through confiscation or malware”.

According to the Telemetrio database, about 33,000 Telegram channels are active in Ukraine.

Ukrainian media estimates that 75 percent of Ukrainians use the app for communication and that 72 percent saw it as a key source of information as of the end of last year.