HONG KONG (AP) — Hong Kong officials said Thursday they are seeking the return of citizens who traveled to Southeast Asia for jobs that entrapped them in scams and virtual slavery.

The victims, who also came from Taiwan and mainland China, took jobs in call centers that sought to cheat Chinese speakers into making payments on fabricated bills and government fees.

Michael Cheuk, undersecretary of Hong Kong’s Security Bureau, said the police and immigration department had received requests for help in bringing back 20 people since January, with 12 of them now safe, although two remain in Myanmar.

Cheuk said officials have not been able to identify the exact location of the eight remaining Hong Kong citizens.

“Our immigration officers are trying their utmost and reach out to the Chinese Embassy and the local consulate generals and explore all the means and avenues and try to secure their safe return," he said.

The scam networks, which often have links to transnational organized crime, are set up overseas to avoid detection, luring educated young workers with promises of high earnings. The workers are then subject to isolation and the threat of violence unless they succeed in cheating victims in mainland China reached by phone into transferring payments into overseas bank accounts.

Taiwanese media have also reported on people being taken to Cambodia after being told they could earn tens of thousands of dollars a month working for financial companies. Myanmar, which remains in crisis after a military takeover, is another location favored by the scammers, with many victims passing through the regional transport hub of Thailand.

The scammers have operated for years, working out of locations as far as away Nepal and East Africa. China has sought to quash the practice, but the schemes appear to remain successful, playing on a strong deference to authority and fear of reprisals among the victims.