The Chartered Institute of Bankers of Nigeria, CIBN, has said Nigeria's usage of bitcoin has continued to rise despite warnings by the Central Bank of Nigeria that digital currencies are not legal tender.

Bitcoin dropped more than 10% over the weekend to a two-week low as fears of a crackdown of cryptocurrencies grew on mounting scrutiny of Facebook’s planned Libra digital coin.

Bitcoin pulled back from 18-month highs on Monday after jumping more than 10% over the weekend, with analysts ascribing the spike to growing optimism over the adoption of cryptocurrencies after Facebook unveiled its Libra digital coin.

Facebook already rules daily communication for more than two billion people around the world. Now it wants its own currency, too. The social network unveiled an ambitious plan Tuesday to create a new digital currency similar to Bitcoin for global use, one that could drive more e-commerce on its services and boost ads on its platforms. But the effort, which Facebook is launching with partners including PayPal, Uber, Spotify, Visa and Mastercard, could also complicate matters for the beleaguered social network. Facebook is currently under federal investigation over its privacy practices, and along with other technology giants also faces a new antitrust probe in Congress.