Vietnamese authorities in the northern Thanh Hoa province have arrested nine locals who had been running and organising an online gambling ring, with transactions totalling almost ₫4tn (US$170m).

In 2017, Vietnamese authorities legalised sports betting for citizens aged over 21 with a monthly income of at least ₫10m and allowed them to play in a casino in the southern Phu Quoc Island. Online gambling in Vietnam, however, remains illegal.

The police are currently trying to locate and arrest the alleged ringleader, a 30-year-old man named Tran Quang Truong. The officers have blocked ₫6bn in bank accounts used by the online gambling ring.

Those who place a bet in Vietnam totalling ₫2m or more, and bookmakers whose ring involves ten or more people, will be charged with criminal offences.

Last week, Vietnamese police detained over 30 people for running two online gambling rings. The illegal rings contained 113 bookmakers, which had accepted bets worth over ₫2tn.