Ukraine has banned Telegram from being used on official devices, with officials concerned Russia can use the app to spy on users and messages.

According to Reuters, Ukraine’s National Security and Defence Council made the decision following a report by Kyrylo Budanov, head of Ukraine’s GUR military intelligence agency, in which evidence suggests Russia’s intelligence agencies are able to access Telegram data. Of note is the fact that the ban only applies to official devices, not personal use.

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Telegram, and its founder Pavel Durov, have long claimed that the platform rivals or exceeds the security provided by Signal or WhatsApp. Virtually all security experts dispute that claim, especially since Telegram chats are not encrypted using end-to-end encryption (E2EE) by default. Instead, the feature has to be specifically enabled by the user.

That lack of E2EE may well be at the heart of the French case against Pavel Durov, with French authorities accusing the executive and his company of not properly moderating illegal content on the platform. Because Telegram does not enable E2EE by default, Telegram cannot make the claim that it can’t access the content, and therefore can’t moderate it.

Budanov made clear that his recommendation was not based on issues with freedom of speech, but rather out of national security concerns.

“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 a statement.