China has observed a higher incidence of underground casinos, with some using online chess rooms to solicit gamblers, said China's top procuratorate on Monday.

Between January and September, prosecutors across the country made 25,140 prosecutions and charged 63,238 individuals for running gambling houses, said the Supreme People's Procuratorate (SPP).

This represents an increase of 49.27 percent and 45.71 percent respectively from the averages of the same period in the years from 2018 to 2020.

A total of 255,850 individuals were prosecuted on the charge from 2018 to September 2021, according to the SPP.

There is a stronger cross-border element in comparison with other crimes in China, said the SPP at a press conference.

New types of casinos tend to be more deceptive and insidious, as criminals may use online chess rooms to lure people into gambling traps.

The crime also involves longer criminal chains, more suspects, and often criminal gangs, added the SPP.

The crime has proved to be hazardous to society, as some gambling websites had as many as hundreds of thousands registered members, said Miao Shengming, an official at the SPP.

The SPP pledged strengthened research into new types of gambling, a joint effort to beef up exit and entry administration and clamp down on black-gray industrial chains in cyberspace, and improving public awareness of such criminal activities.

Gambling has been outlawed on the Chinese mainland since 1949. People who run gambling houses will be sentenced to not more than five years in prison or five to 10 years in severe cases.