BEIJING - Police have busted several cross-provincial criminal gangs that produced gambling machines and ran casinos, according to a statement issued by the Ministry of Public Security on Friday.

Police broke up 16 "black mills" that were producing gambling machines, as well as closed 115 gambling venues spanning 18 provincial regions during their crackdown. Police also arrested 836 criminal suspects and confiscated 3,798 gambling machines, as well as illicit funds worth more than 20 million yuan ($3.17 million).

The gambling rings, which operated publicly by claiming to be animation companies, were headquartered in the city of Guangzhou in southeast China's Guangdong province, producing gambling machines and selling them to affiliated venues across the country, the statement said.

One of the companies, the Guangzhou Beisite Group, had been producing the machines since the end of 2007 and ran casinos in 18 provincial regions, raking in annual profits of approximately 100 million yuan, the statement said.

The ministry said it has destroyed the source of the gambling rings and will maintain a heavy-handed approach against gambling.