At about 1.15 pm on August 18, authorities stopped two men travelling by motorbike from Muong Tinh B Village towards the centre of Xa Dung Commune after noticing suspicious behaviour.
During a search, officers found a black backpack being carried by the passenger. It contained 15 rectangular packages wrapped in moisture-resistant nylon, each containing a compressed white powder suspected to be heroin.
The packages had a combined weight of about 5.25kg.
The suspects were identified as Giang A Senh, born in 2003, and Giang A Di, born in 2000, both residents of Xa Dung Commune, Dien Bien Province.
The two men allegedly told investigators that the 15 packages contained heroin and that they had been hired to transport the drugs to Lao Cai Province for sale.
They said the person who hired them was an unidentified Lao national.
Authorities are continuing to investigate the case.