South Korea’s government announced tougher measures to crack down on cryptocurrency trading in the country and said it is considering shutting down the nation’s bitcoin exchanges, stepping up its attempts to curb widespread investor speculation fueling the market.

New proposed legislation in Korea will ban the use of anonymous cryptocurrency accounts starting next month and prevent banks from providing settlement services for unidentified digital-currency trades on bitcoin exchanges, according to a statement from the government on Thursday.

The government also cautioned that digital currencies could be “vulnerable to the damage from investment fraud or hacking attacks on the exchanges.”

Last week, Youbit, a Seoul-based cryptocurrency exchange, suspended trading and filed for bankruptcy after it was hacked a second time in eight months and lost a chunk of its digital currency reserves. Investigators in South Korea are looking into North Korea’s possible involvement after the exchange collapsed.

The price of bitcoin fell after the new measures were announced Thursday morning in Asia. Bitcoin recently traded at $13,800, according to research site CoinDesk. It has lost more than one-fourth of its value since hitting an all-time high near $20,000 earlier this month.