HO CHI MINH CITY - Vietnam's Ho Chi Minh City has detained 7 foreign and local people for having cheated many victims out of?more than?$400,000 since late last year, local media reported Wednesday.

The seven detainees include two Nigerian citizens named Ihugba Augustine, 30, and Onu Chinonso Peter, 31, who have stayed in Ho Chi Minh City's District 12m and five local people from the city, southern Dong Nai province, southern Tay Ninh province, and central Binh Thuan province, daily newspaper Thanh Nien (Young People) reported.

The frauds' most common trick is informing their potential victims that they are subject to receive big rewards overseas, and they should pay cash to complete legal, customs and banking procedures to get the rewards.

Another trick is that the frauds impersonated wealthy businesspeople to make friends with Vietnamese girls, then promise to send them valuable items or cash. After that, the frauds disguise themselves as customs or police officers to call their victims to force them to pay fees.