China is continuing to push forward in its cryptocurrency crackdown. The People’s Bank of China says crypto transactions are illegal and called for a formal ban. It cited concerns about national security and the safety of residents’ assets.

The bank claims cryptocurrencies aren’t fiat currency and can’t be circulated, as Bloomberg reports. Any transactions involving crypto are now deemed to be criminal financial activity. The bank told financial and internet companies to stop allowing crypto trades on their platforms. Foreign exchanges are banned from providing services to Chinese residents too. 

The rise of crypto has invoked an increase in “money laundering, illegal fund-raising, fraud, pyramid schemes and other illegal and criminal activities,” the bank said. Those appearing to violate the rules will be “investigated for criminal liability.”

Several agencies in the country are working together to clamp down on crypto use. The National Development and Reform Commission is looking to put a halt to crypto mining, as TechCrunch notes. The Sichuan local government banned crypto mining in June, prompting some miners to leave the country.

The price of Bitcoin dropped from around $45,000 to approximately $41,500 on Friday morning, following the announcement.