As part of a broader campaign to curb the illicit flow of capital overseas, authorities in China have reportedly joined with their counterparts in the Philippines to crack down on illegal online gambling operations.

According to a report from the Reuters news service, the coordinated assault comes amid warming ties between Chinese president Xi Jinping and his Philippine counterpart, Rodrigo Duterte, with the latter pledging to weed out unscrupulous operators from the country’s booming online gaming industry.

In a first joint exercise last month, law enforcement agencies from the two Asian nations reportedly shut down a trans-national online gambling operation that involved four websites and arrested 99 people while freezing more than 1,000 bank accounts. Although authorities did not specify how long this illicit venture had been in business, they did detail that the syndicate is estimated to have earned more than $87 million before being closed down.

“We have been visited by Chinese police to crack down on these illegal gambling operators,” Martini Cruz, Executive Officer for the Philippines National Bureau Of Investigation’s Cyber Crime Division, told the news service. “They are also targeting possible fugitives who have made our country a sanctuary.”

Reuters reported that Duterte has recently made illegal online gambling the third front in his war on crime behind drugs and corruption while Martini declared that his office is in the process of planning future raids against illicit operators that target Chinese gamblers from the Philippines.

However, the news service reported that authorities have yet to target the practice of proxy betting, which is permitted in licensed casinos in the Philippines and sees remote gamblers utilize a live stream or online platform to give instructions to an agent located inside a bricks-and-mortar casino. These schemes are thought to have significantly contributed to a recent boom in VIP revenues for casinos in the Philippines, which raked in overall takings of nearly $3 billion last year, although they can additionally allow players to escape the attention of authorities in their home countries.

Reuters reported that casino industry executives in the Philippines are worried that any increased scrutiny on proxy betting could impact their bottom lines while Macau-based junket operator Suncity Group explained that the practice had last month accounted for 80% of its business in the nation.

As background, the news service reported that Chinese law forbids its citizens from gambling online or at home while the nation’s Public Security Bureau has made repeated statements since March explaining that trans-national online gambling is harmful to the nation’s economic security, image and stability.