Authorities are keeping an eye on the R3A Highway which is being exploited by couriers in a now not-so-secret path of drug trafficking, despite original hopes the route would be a boost for legitimate business and tourism.
The road, running 1,861 kilometres from Chiang Rai's Chiang Khong district in Thailand to the city of Kunming in Yunnan province in southwestern China via Laos, aims to ease travel for tourists wanting to explore foreign cultures and commerce traders seeking new opportunities in neighbouring countries.
However, the highway is inadvertently making it easier for drug trafficking gangs to smuggle their products in and out of countries near the Mekong River.
The products are mainly the base chemicals (precursors) used in recreational drugs, according to officials.
The traffickers can, in fact, transport drugs by ship along this trans-national river, but authorities found they prefer going over land because "it is more convenient and the R3A is their main route," according to Safe Mekong Joint Operation Centre director Suchip Khotcharin. The centre unites Thailand, Laos, Myanmar and China together in a drug crackdown in the upper Mekong region.
A section of the R3A Highway in Laos is considered the "weakest point", as illegal activity is concentrated there, Mr Suchip said, adding Vientiane has no policy to set up road checkpoints.
The chemicals -- or drug precursors -- are sent to production sites in areas overseen by armed ethnic minority groups, where authorities exercise little control or monitoring, as well as in the Golden Triangle, another drug production base and opium plantation area located in a region where the borders of Thailand, Laos and Myanmar meet.
Recently, Taiwanese authorities told the Safe Mekong Joint Operation Centre that three Taiwanese chemists, who are on the state black list for drug involvement, are staying in the Golden Triangle and Myanmar town of Tachileik, opposite Mae Sai district in Chiang Rai.
"Authorities are checking whether they are involved in drug production in this area," said Mr Suchip.
Illegal activity there is closely monitored by authorities from the four countries, which recognise a need to share information and intelligence reports regarding drug precursors and trafficking along the R3A Highway.
"Up to 80% of drug precursors are found coming from the Indian border," said Mr Suchip, referring to the Myanmar-Indian border.
Mr Suchip said useful information has been exchanged among the participating countries but admitted the authorities could not inspect some areas, such as those controlled by the National Democratic Alliance Army (NDAA) in Myanmar's Shan state.
Chinese authorities also admitted there are between five and six cities in their country where these precursor chemicals are produced for domestic industry but the smugglers have illegally taken shipments out of the country and they end up in the hands of drug traders, he said.
Police at the Nansing border pass in Yunnan are tightening their inspection of cars entering the city of Jinghong, which is linked to the R3A Highway, to look out for suspicious activity, especially cars with no licence plates, said Nansing checkpoint chief Li Desin.
The officers have arrested many Chinese, Thai and Singaporean suspects, he said, adding some drug couriers disguise themselves as tourists.
Chinese authorities say the Safe Mekong Joint Operation Centre is helping crackdown efforts.
"Over the past four months, the smuggling of drug precursors in Yunnan has decreased significantly," said Permphong Chavalit, secretary-general of the Thai Office of the Narcotics Control Board (ONCB), quoting Chinese narcotics control officials.
"Myanmar will also give more importance [to drug trafficking] along its borders with India."
Mr Permphong recently held talks with senior Chinese authorities, including GuoYoubing, secretary-general of the Yunnan Narcotics Control Commission, on the long-term drug crackdown plans under the Safe Mekong Joint Operation Centre.
The members plan to invite Cambodia and Vietnam to join the centre and intensify the cooperation in tackling drug trafficking.
The centre has started inspections of villages along the Mekong River as well as its major piers which serve as "meeting points" for dealers of drug precursors and their finished products, Mr Suchip said.
Thai drug officials believe there are up to 10 drug gangs at those piers, including Sop Luai pier in Myanmar, as well as at the docking areas of some villages. They transport drugs such as speed and heroin, allegedly by hiding them in barges travelling to Thailand.
The drugs are produced in areas occupied by armed minorities such as the United Wa State Army and ethnic Chinese Kokang rebels, as well as the NDAA, the officials said.
They said the Safe Mekong Joint Operation Centre's plans must be carried out to make other areas, including R3A Highway, safe too.
"We need to expand our operations to cover more areas, because drug traffickers tend to change their transport routes once authorities start monitoring them," said Pol Lt Col Myint Hto, of the Myanmar Central Committee for Drug Abuse Control.