According to police, the group operated from Bokeo Province in neighbouring Laos after relocating from Cambodia. Investigators said the operation was directed by four Chinese nationals.
The suspects allegedly posed as police officers and told victims to update the government's VNeID app, allowing them to take control of their phones, access bank accounts and steal money.
Working with Lao authorities, Vietnamese police arrested all 40 suspects during a coordinated operation on July 19 in Bokeo Province.
Investigators seized 56 mobile phones, 49 computers and other evidence. Police said the group is believed to have defrauded more than 1,000 victims nationwide, with preliminary losses estimated at more than VND 5 billion (about USD 191,000).
The suspects were later transferred to Vietnamese authorities through Tay Trang International Border Gate in Dien Bien Province and remain under investigation.