Bitcoin fell nearly 5 percent on Friday after China’s financial institution said it might clamp down on cryptocurrency trading, banning overseas exchanges from providing services to mainland investors.

The largest cryptocurrency was last down 4.6 percent at $42,874, with smaller coins that typically trade tandem with bitcoin also tumbling. Ether fell over 8 percent while XRP slipped 7 percent.

The People’s Bank of China also said it’ll bar financial institutions, payment companies and internet firms from facilitating cryptocurrency trading, and can strengthen monitoring of risks from such activities.

“Crypto markets are in a particularly frail state overall, and these kinds of downswings speak to that; there is a degree of panic within the air,” said Joseph Edwards, head of research at cryptocurrency broker Enigma Securities.

Crypto continues to exist during a gray area of legality across the board in China.”

Shares in cryptocurrency and blockchain-related firms also came struggling with U.S. listed miners Riot Blockchain, Marathon Digital and Bit Digital slipping between 4.1 percent and 5.1 percent in premarket trading. China-focused SOS slipped 1.2 percent while crypto exchange Coinbase Global fell 2.7 percent.

Earlier this year, Chinese authorities said they might clamp down on cryptocurrency mining, sparking a huge sell-off of bitcoin and other coins.