Vietnamese police have arrested 85 people linked to two major illegal betting syndicates that handled a combined $133 million (about Sh17.2 billion) in transactions, as authorities intensify a nationwide crackdown during the FIFA World Cup.

Online gambling is banned in the communist nation, but illegal betting networks continue to thrive, with authorities often stepping up enforcement during major international sporting events.

Police in Ho Chi Minh City said the raids, conducted in late June, dismantled two betting rings operating on an "exceptionally large scale" with a highly organised command structure.

Investigators said the syndicates processed an estimated $133 million (Sh17.2 billion) in illegal transactions since October.

Authorities said the ring leaders admitted they received "master-level betting accounts" from contacts in Cambodia before splitting them into multiple agent and member accounts for online gamblers.