BEIJING (REUTERS) - Chinese police arrested 98 people connected to online gambling networks that handled US$78 billion (S$111 billion) in bets, state media said on Tuesday (Nov 17), the latest in a series of moves to control illegal activity on the Internet.

Police in the southern provinces of Hunan and Guangdong have shut down 12 "gambling dens" since July, but only now announced the arrests, Xinhua news agency said.

The individuals were suspected of "involvement in an online gambling network that has opened more than 500 online casinos, attracting a million members," Xinhua said, adding that an investigation was ongoing.

Gambling has been illegal on mainland China since 1949, though a state lottery does operate.

China is the world's largest Internet market by number of users. It has launched periodic operations to combat illegal online behaviour and recent moves have coincided with a crackdown on online freedom of expression, which has intensified since President Xi Jinping came to power in 2013.

In August, police said they had arrested about 15,000 people for crimes that "jeopardised Internet security" in a sweep that targeted websites providing "illegal and harmful information"and advertisements for pornography, explosives and firearms, and gambling.