But the remaining members have insisted it’s full steam ahead.
The 21 founding companies in the Libra Association - down from 28 when the project was first announced - met for the first time in Geneva on Monday.
A spokesman told the BBC he believed the currency was still on track to launch next year.
But, he added, it would only do so if suitable regulatory approval had been granted.
It comes after a stern warning from the G7 group of nations that Libra risked disrupting the global financial order.
That concern followed a letter to payments providers from US senators Brian Shatz and Sherrod Brown, sent on 8 October, that threatened “a high level of scrutiny from regulators not only on Libra-related payment activities, but on all payment activities”.
Libra Association spokesman Dante Disparte criticised the senators, telling the BBC the letter “stifles private market innovation”.
“At some level it confounds the regulatory process and the law-making process of free market economies,” Mr Disparte said in a phone call on Monday.
The interference created a “problematic precedent for the state of private sector innovation”, he added.