Singapore has vowed to remain vigilant to keep illicit financial activities in check amid a widening money laundering probe involving 10 foreign nationals who were arrested last month on charges of illegally amassing assets worth more than S$1.8 billion ($1.3 billion) in the last few years.

“We have been diligent from very early on,” Heng Swee Kiat, deputy prime minister and coordinating minister for economic policies, told the Forbes Global CEO Conference in Singapore. “We want Singapore to be a financial center that people can trust.”

About 10 banks including DBS Group Holdings, the country’s largest lender, as well as the local units of Citigroup and Credit Suisse, have so far been drawn into the scandal as the investigation continues. The crackdown, one of the largest money laundering cases in Singapore, has exposed loopholes in the city-state’s financial regulation with the suspects buying upscale properties, gold, luxury cars, cash, cryptocurrency and even exclusive golf club memberships.

Heng—Singapore’s former finance minister and managing director of the central bank—says financial centers around the world will continue to face the challenge of thwarting money laundering activities because there’s a lot of money moving around. “It is a call for all of us to be very, very vigilant because every transaction has a financial element. Our being vigilant is a plus and we have every intention to keep it that way.”

Maintaining robust regulatory standards remains crucial as Singapore, one of the world’s top investment locations, sees increasing capital inflows. “It is important for us to keep integrity in finance and keep its ability to function effectively,” said Heng.