THE MEKONG RIVER -- The Lao People's Army patrol boat was custom-made in China with night-vision capability and two of the most powerful engines on this remote stretch of the Mekong River.
Today, like most days, it sits idle for lack of gasoline, guarded by a single Lao soldier in flip-flops.
Even occasional patrols by boats like these, supplied by China to the Lao army and Myanmar police, have successfully subdued the pirates who once robbed the Mekong's cargo ships with impunity since Chinese-led joint patrols began in 2011.
Flags flutter on a boat while a delegates from China's Narcotics Control Bureau, the United Nations Office on Drugs and Crime, Laos, Myanmar and Thailand travel on an inspection trip on the Mekong River near the border between China, Laos and Myanmar March 1. (Reuters photo)
But there has been little progress on another objective -- stemming the flood of illicit drugs -- exposing the limits of China's hard power in mainland Southeast Asia even as Beijing accelerates its militarisation of disputed islands in the South China Sea.
While attacks on Mekong shipping have tailed off, drug production and trafficking in the untamed region, known as the Golden Triangle, is booming - despite the presence of Chinese gunboats and units of Chinese armed police along the Mekong.
The United Nations Office on Drugs and Crime (UNODC) estimates that Southeast Asia's trade in heroin and methamphetamine was worth US$31 billion in 2013.
"That's bigger than the economies of some Southeast Asian countries," says Jeremy Douglas, the UNODC's Asia-Pacific chief. "It's like having an undeclared sovereign state in your midst with no borders and lots of money."
Enter another Mekong boat, looking at first glance like a pleasure cruiser filled with middle-aged tourists. In fact, they are senior police and drugs experts from four countries, among them one of China's top anti-narcotics officials, Wei Xiaojun.
Arranged by the UNODC and lent further clout by Mr Wei's involvement, their recent voyage down the Mekong was aimed at mustering the regional collaboration needed to tame the Golden Triangle.
Thai soldiers stand guard at Ban Kaen Kai operation base on the Mekong river at the border between Thailand and Laos March 3. (Reuters photo)
Reuters was invited to join the four-day trip from the Chinese port of Jinghong through the heart of the Golden Triangle.
Mr Wei, who is deputy secretary-general of China's National Narcotics Control Commission (NNCC), called drugs the "main threat" along the Mekong.
"All other types of organised crime are rooted in the drug business, like human trafficking, money laundering and the illegal wildlife trade," he said.
Crazy medicine
China is a favourite destination for Myanmar's drugs, which are flowing through Asia in unprecedented quantities.
A long boat sails near the port of Chiang Saen on the Thai side of the Golden Triangle at the border between Thailand, Laos and Myanmar in the Mekong River March 3. (Reuters photo)
More than 250 million methamphetamine pills, better known by their Thai name ya ba or "crazy medicine", were seized in East and Southeast Asia in 2013, an eight-fold increase from 2008.
Seizures of "crystal meth" or "ice" -- a potent, crystalline form of methamphetamine dubbed "the poor man's cocaine" -- doubled during the same period.
In 2015, China seized a record 36.5 tonnes of methamphetamine, said the UNODC, with most of the drug in pill form coming from Myanmar. Myanmar is the world's second-largest producer of opium, the bulk of which ends up in China as heroin.
A recent report from the NNCC raised concerns about the involvement of some Chinese military personnel in drug trafficking, and said the number of registered drug users in China rose to more than 2.3 million in 2015.
Increasingly Myanmar too has a drug problem, with police last year making record-breaking busts of both ya ba and ice.
This could severely test the new government of Aung San Suu Kyi, whose National League for Democracy party has yet to formulate drug policies, say experts.
'Off the grid'
Many factors combine to help the Golden Triangle's drug industry prosper.
A man sits on a long boat on the Mekong River near the Golden Triangle at the border between Laos, Myanmar and Thailand March 1. (Reuters photo)
The Myanmar-Laos border, which the Mekong delineates, is mostly unguarded. The terrain is rugged and hostile, with rebel armies holding sway in some areas and drugs and money-laundering flourishing in lawless enclaves on both sides of the river.
Regional law enforcement agencies are often underfunded and ill-trained, and the intelligence they gather is not effectively shared with neighbouring countries.
In October 2011, a gang led by a Mekong pirate called Naw Kham murdered 13 Chinese sailors. He was hunted down in Laos, then taken back to China to be tried and executed.
The Blue Shield casino operated by the Kings Romans Group stands in the Golden Triangle special economic zone on the banks of the Mekong River in Laos near the border between Laos, Myanmar and Thailand March 2. (Reuters photo)
Afterwards, Chinese gunboats began patrolling further downriver, extending China's security reach far beyond its borders.
This includes a riverside facility in Muang Mom in Laos, which Reuters visited, run and guarded by a 25-strong unit of Chinese People's Armed Police.
China conducts monthly joint patrols with its Lao and Myanmar counterparts, who -- gasoline permitting -- do additional patrols by themselves.
There have been successes. In 2013, a Chinese-Lao patrol found 580 kilogrammes of ya ba, worth more than 100 million yuan ($15 million), hidden in a cargo ship.
But more patrols were needed, said the UNODC's Mr Douglas, and Mekong countries also needed to coordinate and share intelligence to interdict more drugs.
Black holes
Some areas remain intelligence black holes. Hsop Lwe, for example, is Myanmar's busiest port on the Mekong, but its government has no control over it.
The port belongs to Special Region 4, a semi-autonomous enclave famous for gambling, prostitution and narcotics. To the north is Special Region 2, also controlled by heavily armed rebels.
The Special Regions were "off the political grid," said Mr Douglas, although he hoped Mrs Suu Kyi's new government would engage with and secure better access to them.
The UNODC boat could not get permission to stop at Hsop Lwe, where a Chinese cargo ship was unloading SUVs as it passed.
A Thai military post is seen near the port of Chiang Saen on the Thai side of the Golden Triangle at the triple border between Thailand, Laos and Myanmar in the Mekong River March 3. (Reuters photo)
Reuters reporters also spotted unofficial Mekong ports in Laos, which this year chairs the Association of Southeast Asian Nations (Asean).
Landlocked and impoverished, Laos shares a border with all the Mekong countries, which also include Vietnam and Thailand, making it an important smuggling hub for both narcotics and the chemicals that make them.
From Vietnam, for example, comes tonnes of caffeine, used in methamphetamine production and spirited through Laos and across the Mekong in rice bags. Other lawless areas were being created by the Mekong itself.
The ever-shifting river created islands where drug shipments were hidden, said Col Patpong Ngasantheir of the Royal Thai Army. But according to a treaty negotiated while Laos was still a French colony, these islands were deemed neutral.
"We're not allowed to search them," he said.