Chinese police have rounded up more than 1,000 people involved in an online gambling network, freezing bank accounts worth about $53 million (330 million yuan), state news agency Xinhua said.
The suspects were detained in a sweep from June to December last year and 570 people have been put in formal detention, Xinhua said late Wednesday, citing police in the southern province of Guangdong.
The group was led by two men from Guangdong's Shantou city, who built around 200 gambling websites mostly using servers based in Thailand, the report said.
Hundreds of people were detained last year in the southern city of Dongguan, which lies close to Hong Kong, in a crackdown on prostitution and gambling dens.
Gambling is largely banned in China, apart from the self-administered former Portuguese territory of Macau, although there are Chinese government-run sports and welfare lotteries.
Gambling revenue in Macau plummeted 39 percent in March, the second worst on record, as Chinese President Xi Jinping's campaign against corruption kept high-rollers away.