NATO has officially banned staffers from downloading the social media app TikTok onto their NATO-provided devices, citing security concerns, according to two NATO officials familiar with the matter, Report informs referring to CNN.

NATO officials sent a note to staff on Friday morning announcing the ban, the officials said. The note made the ban official, but TikTok was not really usable on NATO-issued devices before, anyway, the officials said, because of internal tech restrictions.

“Cyber security is a top priority for NATO. NATO has robust requirements for determining applications for official business use. TikTok is not accessible on NATO devices,” a senior NATO official told CNN.