Another influential financial commentator is disparaging cryptocurrencies amid a run-up in prices.

In an interview with Business Insider Poland, Nouriel Roubini, an economics professor at New York University's Stern School of Business, expressed bearish views on bitcoin and its brethren, calling the ongoing price gains "a gigantic speculative bubble."

Roubini, who earned the nickname Dr. Doom for predicting the 2008 financial crisis, said that while blockchain technology is promising, bitcoin lacks "serious" payment and capital storage methods and that there is no fundamental reason for current price levels. Rather, bitcoin "feeds on itself," he said.

His comments followed similar remarks in recent months by JPMorgan Chase CEO Jamie Dimon, who called bitcoin a fraud, and Warren Buffet, the billionaire investor, who said bitcoin is experiencing "a real bubble."

"What’s more – it is also used by criminals, for their shady business. I think that more and more countries will start to make cryptocurrency exchanges illegal like China did. New regulations will be adopted. So, this will find its end," Roubini added.

Roubini's comments come as bitcoin's price has been setting new records, surging as high as $7,879.06 today on the news that the Segwit2X hard fork had been called off.

Yet Roubini is not new to bashing the world's first cryptocurrency. In 2014, he called bitcoin a Ponzi scheme and criticized its volatility and the infamous collapse of the Mt.Gox bitcoin exchange.

Roubini image from CoinDesk archives.