William Dudley, New York Federal Reserve President, on Thursday offered the latest critique of cryptocurrencies.

Speaking at a media briefing in Manhattan to discuss the economic outlook for Puerto Rico in the wake of a spate of catastrophic hurricanes, Dudley said there’s a “speculative mania” around cryptocurrencies, which he described as dangerous.

Dudley’s comments come a day after Bank of England Gov. Mark Carney said bitcoin has failed as a currency and a store of wealth.

Read: Bitcoin ‘has pretty much failed’ as traditional money, says Bank of England’s Mark Carney

Since trading below $6,000 on Feb. 6, the price of bitcoin BTCUSD, -3.39%  has more than doubled in the space of two weeks, trading to $11,767.56. However, 36-hours later it has shed more than 15%, underlining one of the chief criticisms of the asset: its volatility. Bitcoin was most recently sinking below $10,000 in recent trade.

Dudley and Carney are among a host of high-profile officials to deliver warnings about the nascent virtual-currency market that has ballooned in popularity.

popularity of cryptocurrency trading. Earlier this month, the head of the Bank for International Settlements (BIS), Agustin Carstens called bitcoin a “Ponzi scheme” and said cryptocurrencies could become “parasites” on the global financial system.