Bitcoin plunged to a six-week low Tuesday after comments from South Korea’s finance minister renewed worries about a crackdown in one of the largest markets for digital currency trading.

South Korean Finance Minister Kim Dong-yeon said in a radio program interview that “the shutdown of virtual currency exchanges is still one of the options” the government has, according to an English-language report Tuesday from South Korea’s Yonhap News.

Last week, it emerged that South Korea was reportedly moving to rein in speculative cryptocurrency trading with a potential bill to ban cryptocurrency trading. The country’s government has since toned down its stance, and on Monday said it would only make a decision on how to move forward after “sufficient consultation and coordination of opinions.”

Bitcoin dropped more than 17 percent to a low of $11,182.71 on Tuesday, falling below $12,000 for the first time since December 5, according to CoinDesk. CoinDesk’s bitcoin price index tracks prices from cryptocurrency exchanges Bitstamp, Coinbase, itBit and Bitfinex. As of 12:13 p.m. ET, bitcoin was trading more than 13 percent lower at $11,759.73 a coin, according to CoinDesk.

Trading in South Korean won accounted for about 4 percent of bitcoin trading volume, according to CryptoCompare. U.S. dollar-bitcoin trading had the largest share at 40 percent, the website showed.

Other major digital currencies including ethereum and ripple also fell significantly. According to CoinMarketCap data, ethereum was trading at $1,051.83, down more than 20 percent in the last 24 hours, before lifting slightly to $1,117.72. Ripple fell almost 27 percent to $1.33 a token before recovering slightly to $1.36.

Investors also monitored reports of an escalated crackdown on the cryptocurrency market in China.

On Monday, Bloomberg reported that authorities in China were planning to block domestic access to Chinese and offshore cryptocurrency platforms that allow centralized trading. Regulators will also target people and companies that provide market-making, settlement and clearing services for centralized trading, the publication said, citing unnamed sources.