Authorities in Greece have broken up what they’re calling a major illegal gambling ring that catered to a predominantly Asian ex-pat clientele.

On Friday, Alternate Minister of Public Order and Citizen Protection Nikos Toskas held a press conference to trumpet the takedown of an illegal electronic gambling ring operating out of five rented luxury houses in affluent suburbs of Athens.

Toskas said the authorities had been investigating the gambling ring for around six weeks and began raiding the various homes on Thursday. The raids resulted in the arrest of three Greek citizens and 125 foreign nationals, whom Toskas said hailed primarily from Taiwan.

Police said the gambling ring was led by a group of 18 individuals, most of whom were also Taiwanese, but included a Greek real estate agent. Toskas said the operation was technically sophisticated, using closed circuit television systems to monitor the perimeter of the properties.