On Friday, bitcoin fell to as low as $81,104, the lowest since November 21, while the U.S. dollar gained after former Federal Reserve Governor Kevin Warsh was selected as the next Fed chair. There are concerns that he might tighten up on cash in the financial system.

Ether also fell 11.76% to $2,387.77 on Saturday afternoon as cryptocurrencies have been struggling for direction since last year's tumble, having been left behind by big rallies in gold and stocks.

Cryptos are having a rough time in what was once hoped to be a golden era of flows and friendly regulation under President Donald Trump, with the market-leading bitcoin losing a third of its value since striking record highs in October.