From Andrew Marshall in Bangkok

THE three-year insurgency in Muslim-dominated southern Thailand has now claimed more than 1800 lives, but the militants who wage it have been notoriously secretive and tight-lipped. But not Roheng, a pseudonym for a commander who controls 250 fighters in the region. He meets me in a public park in broad daylight, an ill-concealed revolver tucked beneath his anorak - a measure of how confident the insurgents have become. "Right now we're winning," he boasts. "Why? Because the villagers support us."

Since prime minister Thaksin Shinawatra was toppled by a bloodless military coup on September 19, the violence in the country's three southernmost provinces has escalated dramatically, despite an unprecedented mood of conciliation in Bangkok. Surayud Chulanont, Thaksin's junta-appointed replacement, has made the south a priority, putting local authorities on alert after intelligence reports suggested the militants would step up attacks over the new year period.

Surayud has apologised for the government's previous iron-fisted polices, including the notorious Tak Bai protest in which 85 Thai Muslims were either shot or suffocated to death in army trucks in 2004. His government has also revived a special peace and development agency.

Despite these gestures, the death toll continues to rise.

The Malay-speaking south has been dogged by unrest since Thailand annexed what was then, a century ago, an independent sultanate. The latest round of violence began in January 2004 after insurgents raided a local armoury, killing four soldiers and stealing more than 300 weapons. Unlike past insurgent groups, today's militants never claim responsibility for attacks or even give themselves a name. The conflict is often mistakenly described as a religious war, pitting Muslims against Buddhists. But while Buddhist police and soldiers remain prime targets, the militants are now killing more Muslim civilians than ever, usually on suspicion of spying for the authorities.

All suspected informers - men, women, teachers, even Muslim religious leaders - are legitimate targets, insists Roheng. "It doesn't matter who you are," he says. "If you spy on us, we'll take you out."

But not all villagers support Roheng. Ismae (not his real name) is a lanky youth in his mid-teens whose father was shot dead by militants a year ago. His village lies in what the Thai military terms a "red zone" of insurgent activity.

"The moment you enter my village, all eyes are upon you," he says.

Soldiers patrolling its streets recently were injured by a bomb rigged to a tree. Most drivers are too scared to go there - and outsiders are unwelcome. Even a passing ice cream seller was fatally shot on suspicion of spying. The village is run by a 100-member militant cell, led by a former Islamic teacher in his 40s.

"This is the man who killed my father," says Ismae, who still passes the leader in the street. "He still smiles at me." While Ismae refuses to join the militants, several friends have.

They swore allegiance to the cell on the Koran, then ate a piece of paper bearing 24 vows written in Arabic script, washed down with water blessed by the village holy man.

Membership is for life. "After you've drunk it you don't feel fear," says Ismae. "If you want to quit, you have to either flee the area or stay and be killed."

A new recruit's first task is scattering leaflets bearing death threats or diatribes against "Siamese infidels" (Siam is the old name for Thailand) and the signature "Fighters of Pattani".

Recruits graduate from vandalism - burning the Thai flags that villagers are ordered by the authorities to display outside their homes - to actual militant attacks, acting as a lookout or helping to block roads. Eventually, they will plant homemade bombs in public places.

Some analysts fear that foreign terror groups, such as the al-Qaeda-linked Jemaah Islamiyah, might help to fund or train Thailand's militants. There is no evidence of this. "We have no problem with funding," says Roheng, whose war chest is boosted by donations from "very rich Muslims" living in the south. The militants in Ismae's village are mostly funded by membership fees. Joining their ranks costs 240 baht (about £3) a year, plus a daily contribution of one baht and a handful of rice. "Every time you cook rice, you take one fistful and set it aside for them," explains Ismae.

While the conflict is often termed a separatist one, Roheng is not fighting for independence.

"We can live within the Thai state," he says. "But only a Thai state in which Muslims have a greater say."

Roheng also wants the withdrawal of extra troops and armed police sent to the region by Thaksin. They commit atrocities and "disrespect our women", he says. "Their presence affects our culture, our religion, our whole way of life." If the troops don't pull out? "Then the fighting will never stop," he warns.