Most of them escaped during the investigation stage and changed their names, forged documents, hide in remote places and sometimes even have plastic surgery to change their appearance, the ministry’s Drug Crime Investigation Department said at a meeting held in Hanoi on Friday to review how the search for drug-related criminals fared in the last 10 years.

Some have fled the country but continue to operate from abroad, transporting drugs to the country using sophisticated methods, the department added.

From 2010 to the end of the second quarter of this year the police have busted more than 208,000 drug-related cases, detaining 322,000 suspects, seizing nearly 7.8 tons of heroin, 11.7 tons of synthetic drugs and more than five million synthetic drug pills.

The quantity of heroin seized in 2019 was seven times the figure in 2010 while the amount of synthetic drugs had increased 342 times.

Major General Nguyen Van Vien, head of the department, said in recent years drug crimes have tended to increase globally and in Vietnam’s neighborhood region, and their scale too has been increasing.

"Some wanted drug criminals continue to lead drug trafficking rings."

For instance, Nguyen Thanh Tuan and Nguyen Van Thuan, who were wanted for the trafficking of 890 kilograms of heroin, escaped into Ta De village in Long Luong, a known drug haven in the northern Son La Province, and built tunnels to store weapons. In 2018 the two were shot dead during a four-day operation that involved more than 300 police officers.

Deputy Minister of Public Security Lieutenant General Le Quy Vuong said drug crimes are considered extremely dangerous and so the police have to adopt all kinds of methods to stop them.

The police are increasingly breaking up drug trafficking gangs led by foreigners.

In July they discovered a large-scale methamphetamine trafficking operation led by South Korean man Kimsoosik, 60, a former police officer, and took in dozens of people, many of them foreigners.

In May 2019 they arrested two Taiwanese and one Chinese men and seized 500 kilos of ketamine hidden in a warehouse in HCMC, possibly the largest ever haul of ketamine in the country.

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

This is despite Vietnam having some of the world’s toughest drug laws. Those convicted of possessing or smuggling more than 600 grams of heroin or cocaine or over 2.5 kg of methamphetamine could face death.

The production or sale of 100 grams of heroin or 300 grams of any other illegal substance is also punishable by death.