AFP takes a look at why the crackdown is happening now and the broader implications for relations between the three countries.

-- Why a crackdown now? --

Cyberscam centres -- hubs for online fraud including investment and romance scams -- have afflicted Southeast Asia for several years, evolving from casinos in the Golden Triangle area on the Thai-Myanmar-Laos border.

When the Covid-19 pandemic hit, the casinos shifted their operations online, becoming increasingly hi-tech and lucrative -- an industry analysts say is now worth billions of dollars.

After a major crackdown in 2022 on cyberscam centres in Cambodia's port city of Sihanoukville, swathes more sprouted on the Myanmar-China border until a rebel offensive cleared them out in late 2023.

In the lawless border towns and hinterlands of Myanmar -- which has been in the throes of a civil war since a 2021 coup -- the scam centres have been able to operate largely unmolested.

Their criminal bosses lure people with promises of high-paying jobs, but then force them to defraud people from around the world or face severe punishment and abuse.

The United Nations estimates that as many as 120,000 people -- many of them Chinese men -- may be working in Myanmar scam centres.

Fears were reignited in January when small-time Chinese actor Wang Xing was allegedly trafficked into a scam centre on the Thai-Myanmar border, prompting Chinese netizens to warn against travel to "dangerous" Thailand.

In response, Thai Prime Minister Paetongtarn Shinawatra visited Beijing in early February and cut cross-border electricity supplies to five Myanmar regions.

The visit by a Chinese public security minister to the Mae Sot-Myawaddy border area two weeks later culminated in the repatriation via Thailand of around 600 Chinese nationals thought to be working in scam compounds.

-- What's at stake for the three countries? --

China has said it is "firmly determined to fight cross-border online gambling and telecom fraud" and has promised "thunder-style cooperation" with Thailand and Myanmar to get rid of them.

Beijing faces pressure to take action from victims' families, said Jason Tower of the United States Institute for Peace, adding "there have been massive losses across China".

The transnational criminal networks behind the scam industry have become so powerful that the Chinese state is also beginning to see them as a threat, he told AFP.

Cooperating to fight the gangs is a way to increase overseas influence, Tower added, warning that China building a "web of police influence that extends across the region" could lead to extraditions of human rights defenders and Uyghurs.

The centres have been a thorn in the side of the Myanmar junta's relations with Beijing -- a major ally and arms supplier -- which has repeatedly told the generals to crack down in recent years.

But through unwillingness or inability -- many of the centres lie in areas outside junta control -- the military was unable to satisfy Beijing.

"China has always had an ambivalent relationship with the junta," Paul Greening, an ex-UN senior staffer based in Mae Sot, told AFP.

"By authoritarian inclination they support military style governments but only as far as it furthers their economic interests."

The Myanmar junta has "no interest in cracking down" on the lucrative scam centres, Tower said, but China -- facing growing domestic pressure and economic woes -- has been urging it to clear them out.

As a result, many analysts believe China gave tacit approval to a rebel offensive in October 2023 that seized territory from the junta in northeastern Myanmar, in return for the rebels eliminating scam compounds in the territory they seized.

While less directly implicated, Thailand -- as a transit hub for many trafficked victims from countries all over the world -- hopes to avoid a reputational stain in the eyes of China, its largest source of tourists.

-- Will this crackdown work? --

The three countries last week agreed to carve out a plan for further repatriations, as Myanmar border militias look after thousands of newly released workers.

But this is not the first crackdown on illicit cyberscam compounds in the region and may not be the last.

"The scam centres will relocate as they have in the past and may not even have to do that," said Greening, adding that a few "fairly inconsequential" scam bosses will be offered up as "sacrifice" while the real bosses will get away.

In an attempt to choke the scam operations, Thailand has cut off internet, electricity and fuel supplies to towns on the Myanmar side of the border believed to house them.

Tower said that while this crackdown was "more significant and intense" than those in 2022 and 2023, the scam centres would either move or find new sources of internet connection and fuel.