The executions are part of a wider crackdown by Beijing on centers across Southeast Asia that have been set up on an industrial scale to hunt down fraud victims around the world and conduct kidnapping, prostitution and drug trafficking.

China has executed four people for causing the deaths of six Chinese citizens and running a fraud and gambling business worth more than $4 billion outside Myanmar.

The Shenzhen Intermediate People’s Court in southern China announced the execution in a statement Monday morning. However, the timing of the execution is unclear.

The executions of 11 more people convicted of running fraud centers in Myanmar were announced last week.

In November, a Shenzhen court sentenced five people accused of running a fraud center and casino network to death. One of the defendants, gang leader Bai Suocheng, died of illness before the execution of his sentence.

The group established an industrial park in Myanmar’s Kokang region on the border with China, where they allegedly engaged in gambling and telecommunications fraud, involving kidnapping, extortion, forced prostitution, and drug manufacturing and trafficking.

The court said they defrauded victims of more than 29 billion yuan ($4.2 billion), killing six Chinese citizens and injuring many others.

The court stated that their crimes were “extremely heinous, the circumstances and consequences were particularly serious, and they posed a huge threat to society.”

The defendants appealed against the first-instance judgment, but the Guangdong Provincial Higher People’s Court rejected their application.

The execution is Wider repression Beijing has cracked down on scams in Southeast Asia, where scam parks have become an industrial-scale operation, particularly in Myanmar, Cambodia and Laos.

Trafficked persons and voluntary laborers perpetrated digital scams against victims around the world, including thousands of Chinese citizens.

Authorities in the region face growing international pressure from China, the United States and other countries to address the epidemic of crime.

Experts say most of the centers are run by Chinese-led criminal groups working with Myanmar armed groups to take advantage of the country’s instability amid ongoing war.

Experts say Myanmar’s junta has long been accused of turning a blind eye, but it trumpeted the crackdown last year amid lobbying from China, its main military backer.

In October, KK Park, a notorious fraud center on the Myanmar-Thailand border, was raided and more than 2,000 people were arrested.

However, some of the government-sponsored raids are part of a propaganda campaign aimed at venting pressure from Beijing without hurting the profits of the military’s militia allies, according to monitors.