China increased the number of cross-border gambling tourism destinations on its travel blacklist for Chinese nationals, according to the Ministry of Culture and Tourism. 

The ministry didn't specify which destinations would be added but said the restrictions aim to protect "Chinese nationals' safety and property security."

The blacklist was first announced last August and the destinations were not made public. The ministry implemented the blacklist system, and said "there has been a continual increase of Chinese citizens traveling abroad, including to gambling destinations." 

Gambling is illegal under Chinese law. Last month, China amended its gambling laws to criminalize cross-border casinos organizing or soliciting Chinese citizens to gamble. Penalties for those found guilty of serious breaches will also be increased.

In recent years, a number of destinations in Southeast Asia, including Philippines, Myanmar, Malaysia and Vietnam, have become hotspots for Chinese gambling tourism. 

More than 600 Chinese suspects involved in cross-border gambling were arrested last year in joint operations with police in these destinations, according to the Ministry of Public Security. 

The Philippines, since 2016, has developed a thriving online gambling industry, mostly run by Chinese nationals out of Manila high-rises. The industry is targeted at customers from mainland China, The Diplomat reported.

"Cross-border gambling is often linked with organized gangs, financial fraud, abduction, trafficking, and illegal immigration," Liao Jinrong, international cooperation bureau chief at the Ministry of Public Security, told a forum in Beijing in September. 

Liao added that many overseas gambling houses have detailed information about Chinese entrepreneurs, which poses a huge threat to their safety.

Tuesday, the Chinese embassy in Cambodia issued a notice on its WeChat page, saying "several vicious violence cases have taken place recently in Cambodia with Chinese citizens involved. A few died abroad." 

The embassy urged Chinese citizens to avoid gambling and high-paying recruitment traps and encouraged reports from public as well as the voluntary surrender of offenders.

Public Security Minister Zhao Kezhi last March called for an investigation into major cases of internationally-based online gambling operators catering to Chinese customers and called for the establishment of an internet gambling company blacklist.

Since then, China authorities have shutdown 368 illegal online gaming platforms, uncovered 257 cross-border gambling cases and arrested 11,500 suspects as of last June, according to Inside Asia Gaming.

While analysts expressed varying opinions as to whether Macau, whose economy relies on gambling, would be included on the blacklist, it remains open to conjecture.

"It's a protective measure for the gaming industry in Macau, which is well-regulated and will certainly not be included on the blacklist, " Bob Yeh, with the Institute for Social and Cultural Research at the Macau University of Science and Technology, told South China Morning Post.

The full-year revenues of Macau casinos fell 79% to 60.4 billion patacas ($7.6 billion), according to the Gaming Inspection & Coordination Bureau. Analysts expect a rebound this year.