The Chinese government further tightened the screws on bitcoin and other cryptocurrencies on Friday, vowing to root out what it called "illegal" activity.The People's Bank of China (PBOC) banned crypto mining nationwide, saying cryptocurrencies must not circulate in markets as traditional currencies and that overseas exchanges are barred from providing services to mainland investors via the internet. The PBOC also barred financial institutions, payment companies and internet firms from facilitating cryptocurrency trading. China's central bank said in a statement on its website that Beijing will "resolutely clamp down on virtual currency speculation, and related financial activities and misbehavior in order to safeguard people's properties and maintain economic, financial and social order." A coordinated move with other government agencies was the latest Chinese attack on bitcoin and other cryptocurrencies. In May, China's State Council vowed to crack down on bitcoin mining and trading, claiming digital currencies pose a financial risk to the world's second biggest economy. The price of bitcoin and other cryptocurrencies immediately dropped on Friday in response. Companies involved in the world of cryptocurrency and blockchain-related activities were down as well. Coinbase, the cryptocurrency exchange that went public earlier this year, moved lower in in early-Friday U.S. trading.