South Asia's illegal arms market is full of "Chinese-made weapons" - but many of them may not actually be made in China.
Anti-arms campaigners say that the rifles and machine guns which South Asia's rebel armies buy are manufactured under "an informal franchise" that Burma's rebel United Wa State Army (UWSA) has managed to secure from Chinese ordnance factories.
The UWSA is an ethnic left-wing rebel militia, with an estimated 30,000 fighters. It is accused of being involved in arms dealing and drug trafficking.
It enjoys very close relations with China because most of its leaders, being former Communist guerrillas, were trained in China in the 1960s and 1970s.
Matters have recently become more tense because the UWSA's ceasefire with the Burmese military government is in danger of falling apart.
The UWSA is unhappy over the government's drive to get all ethnic militias to join a military-sponsored Border Guard Force.
None of this seems to bother unscrupulous and unofficial Chinese arms dealers who carry on supplying weapons, despite the possibility of more armed conflict.
"The Chinese factories are desperate for profits and they have not cared who the weapons are reaching. Now they are outsourcing [their know-how]," says Binalaxmi Nephram, an award-winning campaigner against small arms proliferation.
At the same time the UWSA has started producing Chinese-made weapons under an "informal franchise" after allegedly making a huge annual payment to factories in China to use their designs and obtain production-level support.
Sources in the illegal arms trade say that the last big consignment of genuine Chinese weapons to enter South Asia was the one that was seized by Bangladesh police at the port city of Chittagong in April 2004.
Confessions made by a Bangladesh arms dealer, Hafizur Rehman, in a Chittagong court indicated this consignment was being imported from Hong Kong by the United Liberation Front of Assam (Ulfa), a major separatist group in India's troubled north-east.
Rehman said he worked the deal after being paid a hefty advance by Ulfa's military chief, Paresh Barua.
But Mr Barua was not importing this huge consignment for his group alone, say officials.
Over the past 10 to 12 years, Ulfa has emerged as a major player in the illegal arms trade in South Asia.
Buying "Chinese arms" where they are cheapest, the group would then sell them on at a profit to bulk buyers such as Maoist rebels in India and Nepal, it is alleged.
In the process, Ulfa paid for its own arms imports and also built up huge bank balances to finance its separatist campaign.
When Bangladesh's new government cracked down on Ulfa last year and detained almost their entire top leadership nearly $1bn (£0.6bn) was seized from more than 40 bank accounts operated by the group.
Bangladeshi and Indian intelligence officials say that, while a part of these funds was secured through extortion and trading activity, the bulk of it came from the illegal arms trade.
They told the BBC that after the 2004 Chittagong port seizure, Ulfa turned to a new source of Chinese weapons, the United Wa State Army.
Two senior Ulfa rebel leaders, on condition of anonymity, corroborated the intelligence claims.
They said that the weapons manufactured by the Wa rebels were "initially inferior" to those made in China, but within a few months the "production defects were sorted out".
"What we now buy from the Was are a perfect copy of the original Chinese weapons. And they are much cheaper and are also handed over to us at convenient locations near the Indian border," said a leader.
Gaganjit Singh, a former deputy chief of India's Defence Intelligence Agency, said: "Thousands of rifles, machine-guns, pistols and revolvers, grenades and much else went to the Indian Maoists - and before that to the Nepali Maoists - and the jihadi groups of Bangladesh and the separatist armies of north-east India through this conduit."
Chittagong has emerged as the hub of the trade, say officials.
The arms dealers and rebel leaders were spending so much time in Chittagong hotels that Ulfa eventually bought a number of city properties for their meetings.
Senior Bangladeshi officials in the city told the BBC that once Ulfa had the consignments delivered to them, they would use a network of Bangladeshi arms dealers to settle deals with buyers in India, Nepal and Bangladesh.
"The consignment would then be split into small, well-concealed packages and carted off to their destinations," admitted one Bangladesh arms dealer on condition of anonymity.
The conduit fell apart when the Bangladesh government started their crackdown against the Ulfa and other Indian rebel groups.
That has made the principal suppliers, the United Wa State Army, rather desperate.
A representative of the group even contacted me seeking "direct contacts" with India's Maoists.
Indian intelligence is not able to confirm whether the Was have been successful in making "direct contact" with the Indian Maoists.
"But they will keep trying, because they have to sell their increasing stocks of weapons," says Gaganjit Singh.
"And who better than the expanding army of Indian Maoists to pick them up?"