BANGKOK -- Thailand's police on Wednesday detained 100 people for their alleged involvement in a scam centre in Cambodia, its first arrest of Thai nationals in a regional crackdown on massive fraud operations.

Arrest warrants were also issued for two Chinese nationals who were alleged "gang leaders", stemming from a raid of a scam centre last month by Thai and Cambodian police in the Cambodian town of Poipet, Police General Thatchai Pitaneelaboot said.

Scam centres have operated along Thailand's borders with neighbours Myanmar and Cambodia for years, but the high-profile abduction in Thailand of a Chinese actor who ended up in a Myanmar boiler room sparked a multinational effort to dismantle the network. He has since been returned home.

Criminal syndicates have trafficked hundreds of thousands of people to work in sprawling compounds that use sophisticated techniques to trick people into transferring funds, generating illicit revenues running into billions of dollars each year, according to a United Nations report.

In February, Myanmar sent over to Thailand the first group of 260 people taken out of scam centres. So far, about 7,000 people of more than 20 nationalities, mostly Chinese, have been extracted, with some struggling to return home.

Most were victims of human trafficking, according to Thai authorities, who are coordinating repatriations. Police said the 100 arrested on Wednesday were part of the criminal gang running the operation.

They were defrauding victims by impersonating government officials, said Thatchai, who estimated more than 1,000 Thais were still working across borders in scam centres.

Police have said Thais have since 2022 been defrauded of about 80 billion baht ($2.37 billion) in telecoms scams.

"These scam centres are transnational criminal organisations, being carried out by foreigners with Thais to defraud Thais," he said.

This week, Thai Prime Minister Paetongtarn Shinawatra ordered a study on the effectiveness of building a wall on part of its border with Cambodia to prevent illegal crossings and curb illicit activities.