The industry involves sprawling compounds housing tens of thousands of workers, many of them trafficked, who are forced to scam victims around the world.

Cyber scam operators in Cambodia and Myanmar alone have stolen some $10 billion from American citizens in the last year, the US Treasury said on Tuesday, as it imposed sanctions on entities in both countries.

In its report, the UN Office on Drugs and Crime (UNODC) said it had found signs pointing to the "establishment and operation" of such a scam centre in Timor Leste's Special Administrative Region of Oecusse-Ambeno.

Timor-Leste is one of Southeast Asia's poorest nations. At 15,000 sq km (5,800 sq miles), it is slightly bigger than Qatar, with a population of 1.3 million.

Its government did not immediately respond to a request for comment.

On August 25, a raid at a hotel in the Special Region by Timor Leste intelligence and law-enforcement found individuals with links to scam operations, and evidence including SIM cards and satellite internet devices, the UNODC said, adding:

"UNODC's analysis links these operations to entities associated with convicted cybercriminals, offshore gambling operators."

The UNODC has said scam centre operations are spreading globally, especially in Southeast Asia, which indicates that it remains lucrative.

It estimates that hundreds of large-scale scam farms around the world generate tens of billions of dollars in annual profits, and says they are proliferating in Cambodia, Myanmar, and the Philippines, partly due to relaxed local regulations.