Hanoi (VNA) - Vietnamese police are working with their Chinese peers to investigate a drug production ring in the Central Highlands province of Kon Tum.

The Police Department for the Investigation of Drug-Related Crimes under the Ministry of Public Security announced the cooperation on September 15.

It is the biggest inter-country drug production ring found in Vietnam.

Eight people were temporarily held by the police, including seven Chinese people and a Chinese-Vietnamese national.

Head of the ring was Cai Zili, 56, of Chinese nationality. He had previous convictions related to drugs in China including life imprisonment. After receiving amnesty, he went to Vietnam and repeated the crimes.

Earlier at about 6am on August 6 this year, the police caught seven Chinese people in the act of making drugs in a workshop of the Dong An Vien Import Export Co Ltd in Dak Ha town, Dak Ha district in Kon Tum province.

Evidence seized included 140 litres of thick solution tested to contain methamphetamine, about 13 tonnes of chemical substances of different kinds contained in buckets, cans and bottles, and about 20 tonnes of machinery to produce drugs.

Right after the ring was discovered in Vietnam, Chinese police also arrested 22 people./.