By Olena Harmash

KYIV (Reuters) -Ukraine has banned use of the Telegram messaging app on official devices used by government officials, military personnel and critical workers because it believes its enemy Russia can spy on both messages and users, a top security body said on Friday.

The National Security and Defence Council announced the restrictions 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.

But Andriy Kovalenko, head of the security council's centre on countering disinformation, posted on Telegram that the restrictions apply only to official devices, not personal phones.

Telegram is heavily used in both Ukraine and Russia and has become a critical source of information since the Russian invasion of Ukraine in February 2022.

But Ukrainian security officials have repeatedly voiced concerns about its use during the war.

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 has sold.

Durov was arrested upon landing in France in August as part of an investigation into crimes related to child pornography, drug trafficking and fraudulent transactions on Telegram.

The Security 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.

President Volodymyr Zelenskiy, 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.