London | Facebook's ambitious plan to roll out its own cryptocurrency ran into immediate political opposition in Europe, with calls for tighter regulation of the social-media giant.

French Finance Minister Bruno Le Maire said the digital currency known as Libra shouldn't be seen as a replacement for traditional currencies.

"It is out of question'' that Libra "become a sovereign currency,'' Mr Le Maire said in an interview on Europe 1 radio. "It can't and it must not happen."

Mr Le Maire called on the Group of Seven central bank governors, guardians of the global monetary system, to prepare a report on Facebook's project for their July meeting. His concerns include privacy, money laundering and terrorism finance.

Libra was also a talking point at the European Central Bank's annual symposium in Sintra, Portugal, where Bank of England Governor Mark Carney referenced Libra. "Anything that works in this world will become instantly systemic and will have to be subject to the highest standards off regulation," he said.