Chinese police arrested six people involved in using cryptocurrency to provide an illegal currency conversion operation that handled some 2.14 billion yuan ($296 million), according to a China News Service report published on Weixin.

The "underground bank" was uncovered by the Public Security Bureau of Panshi City, Jilin, the state-owned news service said.

The operation used domestic accounts to receive and transfer funds while exploiting the anonymous, borderless characteristics of over-the-counter virtual currency trading to exchange between the yuan and South Korean won. Users included Korean purchasing agents, e-commerce firms and import/export companies, among others, according to the report.