Bitcoin, the world's best-known cryptocurrency, fell more than 10 percent on Monday and approached three-month lows on concerns about a global regulatory clampdown on the trading of the digital coins.
On the Luxembourg-based Bitstamp exchange, Bitcoin traded as low as $7,289 by 1430 GMT, having now fallen by more than half from a peak of almost $20,000 hit in December.
Other cryptocurrencies also suffered double-digit declines in their prices on Monday, according to industry tracker Coinmarketcap.com.
British bank Lloyds Banking Group said on Sunday it was banning customers from buying bitcoin using credit cards.
It joined U.S. banking giants JPMorgan Chase & Co and Citigroup who announced similar bans on concerns the lenders could be held liable when the volatile currencies plunge in value.
And on Monday, India said it was planning steps to make virtual currencies illegal within its payments system and to regulate the trading of crypto assets.
"Cryptocurrencies have seriously fallen out of favour since the middle of December and constant negative news flow and speculation of increased regulation has exacerbated the move lower, much in the same way that the constant flow of positive news stories aided the explosion higher," Craig Erlam, an analyst at currency broker Oanda, said.