Britain and the United States on Tuesday sanctioned a Southeast Asia-based multinational network accused of operating large-scale online “scam centres” that used trafficked workers to defraud victims around the world.

The British government said the centres, located in Cambodia, Myanmar and across the region, used fake job adverts to lure workers who were then forced to commit online fraud under threat of torture.

This included luring victims into fake romantic relationships before persuading them to invest large sums in fraudulent cryptocurrency platforms.

“The masterminds behind these horrific scam centres are ruining the lives of vulnerable people and buying up London homes to store their money,” British Foreign Minister Yvette Cooper said.

The US Treasury Department said it had taken what it described as the largest action ever in Southeast Asia, targeting 146 people within the Prince Group criminal organisation, which Britain also sanctioned.

Britain’s sanctions targeted six entities and six individuals, including Prince Group’s chair, Chinese-Cambodian tycoon Chen Zhi, whom the US and UK accused of having overseen the construction of compounds used for online scams.