Deputy Director of Social Affairs in Dong Nai province, Ho Van Loc, told the newspaper that "over 500 inmates" broke through the gates of the Dong Nai rehab center at around 11pm Sunday evening.
The patients then rushed to the National Route 1A trans-Vietnam highway, where they blocked traffic. By 1am Monday local police had managed to apprehend some of the most violent patients, and later on Monday police reported that 300 had been returned to the custody of the authorities.
Passers-by reported that the escaped drug addicts were "screaming so loudly, scaring people," and threatened them with sticks or machetes to obtain money.
"We are still hunting them in fields and surrounding areas. Many have caught taxis and left the province," he said.
"Their further fate will be decided according to the law. Those who don't have a place of residence will be sent for compulsory treatment. Those who have a place of residence will be returned to their family for rehabilitation and re-education in the community."
Dung said that the inmates were able to escape because of "the negligence of staff, and psychological pressure on those in their care."
"They were motivated by fear that the court would find them guilty," the minister said.
Vietnam has an estimated 200,000 drug addicts, many of whom are heroin users.
A previous outbreak from a drug treatment center occurred in April, when around 450 addicts escaped from a rehab center in the southern province of Ba Ria Vung Tau.