Apple boss Tim Cook has delivered a thinly veiled warning to Facebook over its cryptocurrency project Libra.

While much has been made of Facebook’s plans to democratise finance through Libra and new digital wallet ‘Calibra’, Cook told French newspaper Les Echos that Apple has no such intentions.

“I really think that a currency should stay in the hands of countries,” Cook said.

“I’m not comfortable with the idea of a private group setting up a competing currency. A private company shouldn’t be looking to gain power this way.”

The comments came as PayPal announced it was backing out of the 28-member nonprofit Libra Association that was formed to help get the project off the ground.

It is not the first time Apple has come out and delivered nonspecific criticism of Facebook and other tech giants.

The iPhone-maker famously erected a very cheeky “What happens on your iPhone stays on your iPhone” billboard ahead of this year’s CES conference in Las Vegas, in what was an obvious dig at Facebook and Google’s well-documented privacy troubles.

Similarly, the recently announced “Sign in with Apple” feature is designed to allow users to easily log in to apps and websites without using Facebook or Google as a single-sign-on method.