Facebook’s plans for a digital currency are coming under further pressure as global regulators step up their scrutiny of the struggling Libra project.

In a letter to G20 finance ministers on Sunday, Randal Quarles, the head of the global Financial Stability Board, said that, with a “host of challenges” posed by global “stablecoins”, such as Libra, “possible regulatory gaps should be assessed and addressed as a matter of priority”.

The concerns of the FSB, which represents all large financial centres in the world, centred around the fear that global digital stablecoins could become a substitute for domestic currencies. This, the letter said, created challenges including financial stability, consumer and investor protection, data privacy, money laundering, terrorist financing, fair competition, cyber security and tax evasion.