Vietnamese police have smashed a huge cryptocurrency ring worth around $3.8 billion, state media said Friday, as authorities battle rampant illegal gambling in the country.

Fifty-nine people were detained in southern business hub Ho Chi Minh City, accused of luring players through social media to place bets online, according to the city police's official newspaper.

The gambling ring is reportedly the biggest ever uncovered by Vietnamese police.

State media said players were instructed to buy a cryptocurrency wallet and convert their money into one of two digital currencies, Ethereum or USDT -- also known as Tether -- before placing bets on Swiftonline.live and Nagaclubs.com.

To entice new players, the detainees posted pictures on social networks showing off their fancy cars, expensive houses and extravagant parties.

To sway the more cautious, scammers also offered players insurance packages, with the promise of a refund if they did not win after six games.

However, during periods when there were a large number of players, the ring leaders crashed the websites in order to steal money from the digital wallets and avoid detection by police.

Officers confiscated 55 laptops and desktops, 39 mobile phones and seven luxury cars from the gang in Ho Chi Minh City.

State media said the gang had also established large-scale gambling networks in many other provinces and cities across the country. 

Vietnam's communist government has started loosening its grip on domestic gambling, allowing Vietnamese to bet in casinos and opening up some sports betting.

But online gambling and private card rooms remain banned.

Still, despite regular crackdowns on illegal gambling, rings run by both locals and foreigners continue to flourish.

Last year police uncovered a massive online card ring with revenues estimated at $2.6 billion.