When police entered the Ozone Bar on the fourth floor of the five-star Central Park Hotel in Bien Hoa Town, the southern province of Dong Nai, hundreds of people who were dancing threw drugs on the floor and tried to escape.

Police seized many small plastic bags containing pills and powders.

Out of 250 people taken to the local police station, 150 patrons aged 18 to 30 tested positive for banned substances.

The bar representative could not present legal documents for the business, which has been open since early this month, and 84 employees did not have a labor contract.

Meanwhile police in the northern province of Bac Giang raided the Royal KTV karaoke parlor in Viet Yen Commune and found 66 people high on drugs. As of writing, 49 people, mostly female employees of the parlor, had officially tested positive for banned substances.

Local authorities also confiscated bags of drugs that were being used, apart from four cylinders of nitrous oxide (N2O) and balloons containing laughing gas.

Meanwhile, 28 customers and four employees of the Paradise Karaoke parlor on Le Loi Street in Tam Ky Town, the central province of Quang Nam, also tested positive for banned substances.

The parlor’s owner, 52-year-old Tran Cao Tuyen of Quang Ngai Province, could not show local authorities legal documents for the business.

The use of synthetic drugs has been on the rise among partying youth in Vietnam, multiple reports have noted. Last September, seven people died of suspected drug overdose at a music concert in Hanoi.

Vietnam had more than 222,000 drug addicts as of the end of 2017, with an increasing number of them, especially young partygoers, using synthetic drugs like methamphetamine, ecstasy and ketamine, according to the police.

Drug use is on the rise despite strict legal prohibition and stiff punishments for producing or trading in drugs.

Vietnam has also emerged as a key trafficking hub for narcotics from the Golden Triangle, an intersection of China, Laos, Thailand, and Myanmar that is the world's second largest drug producing area after the Golden Crescent in South Asia.