Police in Son La Province on the Laos border Saturday seized 6.6 kilograms of heroin from a smuggling gang after a shoot-out.
A police source said they started shooting back after the gang of more than 10 people fired at them.
The gang fled after 20 minutes, leaving a gun and the drugs behind.
The police are looking for the smugglers.
Vietnam has some of the world’s toughest drug laws. Those convicted of possessing or smuggling more than 600 grams of heroin or more than 2.5 kilograms of methamphetamine face the death penalty.
The production or sale of 100 grams of heroin or 300 grams of other illegal narcotics is also punishable by death.
Although the laws have been strictly enforced with capital punishment handed down regularly, drug running continues in border.
The Son La police arrested 25 people and seized around 300 kilograms of heroin smuggled in from Laos in a one-year period up to May 2015. This year too many drug smuggling attempts have been busted.