The director of Germany’s central bank believes that bitcoin should be regulated through an international set of rules rather than on a national scale.

Bundesbank director Joachim Wuermeling said that borderless cryptocurrencies are difficult to regulate within a specific region or country, according to Reuters. Speaking at an event in Frankfurt, the banker said cryptocurrencies instead be overseen on a global scale, with regulators harmonizing their rules together.

To that end, Wuermeling said that such a state of affairs could only be reached in the event of heightened cooperation.

He was quoted as saying: “Effective regulation of virtual currencies would therefore only be achievable through the greatest possible international cooperation, because the regulatory power of nation states is obviously limited.”

His remarks follow developments out of China and South Korea on the regulatory front. Notably, South Korea was reportedly planning to shut down exchanges, though those rumors were later walked back by the president’s office.

However, South Korea is acting on new regulations to slow down speculative investing in cryptocurrencies by forcing banks to comply with new know-your-customer rules and imposing fines on investors who refuse to cease using anonymous virtual for cryptocurrencies.

Meanwhile, China has indicated it might try to reduce mining activity by withdrawing tax and power benefits for companies.