In the second of a series of articles from the Thai-Burma border, the BBC's Kate McGeown looks at the small rebel army that has spent nearly 60 years fighting the Burmese government.
The KNLA is a small but determined rebel army
A David and Goliath struggle is raging in the jungles of eastern Burma.
A poorly-equipped force of 12,000 men from the Karen ethnic minority is pitched against 400,000 Burmese government soldiers, complete with AK-47s, tanks and fighter planes.
Most of the once huge array of ethnic rebel armies in Burma's north-east have given up the fight, signing ceasefire deals with the ruling military junta.
The Karen National Liberation Army (KNLA) is increasingly alone - and certainly the largest of the groups remaining. Yet it is gradually being driven further and further back towards the Thai border.
In the past few decades, the KNLA's political wing, the Karen National Union (KNU), has suffered a serious split as well as an abortive peace deal.
To make matters worse, a high-profile general defected in February, just a few months after the death of former leader Bo Mya.
But still the rebels fight on, determined to achieve an autonomous Karen state and protect the Karen people from abuses by the government.
"Whatever happens, we cannot surrender," said KNU leader Pado Mahn Shar. "If the government won't offer us a proper peace settlement, we have to carry on fighting."
"We cannot have our people annihilated by some sort of ethnic cleansing programme," added KNLA head Mutu Sae Po, referring to the growing number of Karen civilians being driven from their homes and even killed by the Burmese military.
The odds are against them, but one thing the Karen rebels have on their side is determination, borne of nearly 60 years of struggle.
Many are veteran fighters - some of whom, like 74-year-old Mutu, grew up absorbing tactics from the British army during World War II, and have already survived decades of jungle combat.
But what can they realistically hope to achieve? The Burmese government - which, according to some external estimates spends about two-thirds of its budget on the military - has tanks, war planes and Chinese and Russian guns at its disposal.
The Karen rebel leaders are veterans of the conflict
The rebels, in contrast, are forced to use whatever they can get hold of: sometimes, according to Mutu, they even deploy Napoleonic-era muskets.
Logic says the KNLA cannot possibly prevail, but Mutu insists otherwise.
"They might have a much larger army, but we can still kill them when we want to," he said.
"We can use people power, like in the Philippines, and we can force the government to hold proper negotiations," added Pado Mahn Shar.
Even those analysing the situation have not written the rebels off.
"The Karen are fighting for something they passionately believe in. The Burmese just want to squash people," said Phil Thornton, the author of the book Restless Souls, documenting life on the Thai-Burma border.
Of course the Burmese government has no intention of letting the underdogs have their way. It has another weapon in its arsenal - a psychological one - which it has been using increasingly in the past few years.
According to reports from refugees who have fled from Burma's Karen state across the border to Thailand, soldiers are now actively targeting Karen civilians in an attempt to persuade them to ask the rebels to give up their fight.
The KNU, through its armed wing the KNLA, has been fighting for greater autonomy since 1949
The KNLA split in half in 1994, with the new group, the DKBA, making a pact with the government
The KNU and the junta reached a 'gentleman's agreement' in 2003, but it quickly broke down
The Karen is just one of many ethnic minorities in Burma. Much smaller rebel groups still exist in the Shan, Karenni and Mon states
By the end of last year, an estimated 500,000 people were internally displaced in Burma, according to the Thai Burma Border Consortium, and thousands more fled to Thailand.
But despite decades of fighting, and the undoubted hardships that local villagers have suffered as a result, there is still an amazing level of civilian support for the KNLA.
"We need to keep fighting, even if there are security risks. We can't trust the Burmese government," said Christopher, a Karen civilian who fled from Burma to a UN-administered refugee camp.
"We still have a huge amount of help from villagers," added a KNLA soldier currently on leave in the Thai border town of Mae Sot.
"I was in a village recently, when a lot of Burmese soldiers arrived. The local people showed me how to leave safely via a back route."
Part of this support is undoubtedly due to the fact that the KNLA - even by its own admission - is primarily a defensive force, fighting back in areas where villagers are being threatened.
Mr Thornton describes the rebels as "almost a paramedic service", and they certainly seem to spend a lot of their time helping Karen civilians across the border to safety.
"They helped us all the way from the jungle to the border, so we knew where to go and didn't tread on landmines," said one recent arrival at a UN camp.
What the KNU really wants right now is international support.
While their cause seems to attract some foreign interest - there are even several Westerners, including Vietnam war veterans, who have taken up arms to help them - the international community as a whole has yet to take any concrete action over Burma's suppression of minority groups.
The military has driven thousands of Karens from their homes
Pado Mahn Shar said he was very disappointed at the recent decision by China and Russia to veto a draft UN Security Council resolution calling for an end to human rights abuses in Burma.
"It's really bad news for our Karen people and the country as a whole," he said.
But whatever the international community decides to do, the Karen rebels look set to carry on their struggle regardless.
"If necessary this conflict will go on for generations and generations. We will never give up," said Mutu.
And it would very unsafe to underestimate his word.
"I might look old, but I can still shoot someone in the head," he said.
In the next piece in the series, Kate McGeown looks at the medics who do their best to help Burmese civilians in the border region - sometimes even risking their lives in the process.
Do you live on the Burma-Thai border? Use the form below to send us your experiences and comments:
I used to visit Mae Sot and Mae La camp quite often as a volunteer working in Bangkok. The situation for the political refugees and economic migrants is horrific. After they are caught by the Thai authorities they are often made to wait for days without food and water before deported to Burma. Those deported back to Burma through the Three Pagodas Pass area are subject to more danger, as it is less populated than Mae Sot. I've seen harassment of Karen refugees by Thai police and military not only in the border regions but also in Bangkok, where many Karen come while being processed to a third country. They are subject to searches and bribes when found out by the police. These Karen often hold official UN refugee status identification. Ryan Hughes, Oregon, US
I am from Thailand and I used to work in three different Karen refugee camps on the Thai-Burma Border. There are several NGOs working in those camps to make sure that the refugees have access to basic commodities. It's true that the Thai government has a strict policy towards illegal migrant workers, but it's also the business owners who encourage this practice. At one point there was a call for all illegal workers to register themselves with the government so that they will be on the record. However, most business owners refused to participate in because it's not in their interest to pay proper wages. Thailand will not be able to absorb all these refugees. Also the resettlement programme in third country is a very lengthy process and only special cases will be considered seriously. The only sustainable solution is to make Burma safe for them to return. Preyapan, Liberia
Three years ago, my wife and I attended a dinner party in France, and were seated at a table with a newly-wed couple. She is Burmese and he is Britist, and they were on their way back to Burma, after their honeymoon in Europe. I was about to ask them how the bride managed to come and go as she pleased, and why would they go back to live under such a regime, when I realized that they were part of the regime. From that point on, I could hardly wait for the meal to end. Were it not for the coddling by a few Western elite, the Burmese elite just might reflect more on their actions. Jonas South, US
I worked in a refugee facility in Mae Sot as a volunteer teacher in 2005. I worked mainly with Karen refugees. I have the tragedies that some of the refugees have experienced, especially children who have lost parents in the struggle and have lived in refugee camps in Thailand for several years. The hopelessness of the situation is daunting, yet the resilience and the confidence of the refugee peoples is both inspiring and humbling. Martin Morris, Australia
Migrants are active in trying to improve their situation in Thailand, both with regards to their working conditions and health care. Many migrants volunteer to be community health workers. Groups of migrants working in exploitative conditions have taken their labour cases through the legal mechanisms in Thailand and through their courage have improved some of these mechanisms. Many of the labour issues faced by Burmese migrants are the same issues faced by local Thai workers and the Thai Labour Solidarity Committee recently petitioned the government to improve the working conditions of migrant workers. Jacie Pollock, Chiang Mai, Thailand