Police in Hanoi Thursday confiscated US$100,000 and over 8,000 euros ($11,578) which were allegedly being illegally traded at a local gold shop.
According to the police, early that day, they caught some people bringing the money from Minh Thiet gold shop in the northern province of Ninh Binh to sell to the Hong Duong shop in Hanoi's Hoan Kiem District.
Initial information shows that it was a professional ring trading in foreign currencies, the police said.
Investigations into the case are ongoing, they added.
Last month, Hanoi police had busted an illegal foreign exchange transaction worth $390,500, said to be one of the largest such transactions caught by the authorities.
Since last month, Vietnam has cracked down hard on illegal dollar hoarding and trading in an effort to stabilize the currency market.