After a long investigation, the police raided the house of Nguyen Dinh Giang, 49, and found 3.5 kg of heroin, nine kg of methamphetamine, and 21,000 ecstasy pills hidden on the roof.

Subsequently, three more men were arrested: Hoang Danh Diep, 38, Nguyen Cong Cuong, 36, and Pham Van Hung, 42. In raids on their homes, an additional 200 grams of heroin and 1,000 ecstasy pills were found.

The four men said they bought the drugs from Laos and delivered them to provinces in the north and south of the country.

The same day, 11 members of a drug trafficking ring were sentenced to death in the northern border province of Lang Son for trafficking 561 kg of heroin from Vietnam into China.

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

Despite Vietnam's tough drug laws including death sentences for making, smuggling and trading in drugs, drug busts have become increasingly frequent in recent years.