China's police have conducted five operations and captured 846 suspects in a campaign the Ministry of Public Security launched in May to crack down on "money changing" in the Macao Special Administrative Region, an official of the ministry said.

Police in multiple regions have collaborated with the police of Macao to crack a number of such cases, Chen Shiqu, deputy head of the ministry's criminal investigation department, said on Friday.

They have dismantled more than 100 "underground banks" and discovered more than 80 billion yuan ($11 billion) of capital flow involved in these cases, Chen said at a news conference held by the ministry in Beijing.

The police have also dismantled 263 organizations suspected of engaging in crimes deriving from "money changing," such as illegal business operations, illegal border-crossing, fraud and false imprisonment, Chen said.

At a news conference organized by the ministry in July, Chen explained that "money changers," or huanqiandang in Chinese, referring to those conducting illegal currency exchange services in cash?in a large amount for individuals or organizations, and lending money at exorbitant interest rates to gamblers, in Macao.