More than 3,000 people have been killed in Muslim separatist unrest in the far south which flared up in early 2004.

The government in Bangkok has sent 30,000 troops to the region, but they have been unable to halt the violence.

Muslims are a minority in Thailand, making up less than 5 percent of the country's total population of 63 million. They live mainly in the southernmost provinces that were annexed by the Thai government in 1902.

Many of Thailand's Muslims speak Malay and have more in common with the majority of the population in neighbouring Malaysia than with Buddhist Thais.

For around 500 years, they belonged to an independent sultanate, called Patani, which comprised the present-day provinces of Pattani, Yala, Narathiwat and parts of western Songkhla.

This history and the persistent political marginalisation of the Malay minority are key factors behind the sporadic violence that has broken out in the region since it was incorporated into Thailand.

The southernmost Thai provinces are poorer than the rest of the country, and their main business sectors - agriculture, fishing and tourism - have been hurt by the violence.

Yet both International Crisis Group (ICG) and Human Rights Watch (HRW) maintain that political grievances are more important in explaining the violence than economic inequality and low levels of development.

Following a lull through the 1990s, conflict escalated sharply in 2004. Arson attacks, bombings and shootings of Thai officials, policemen and even civilians have become an almost daily occurrence.

Working out who is behind the attacks is very difficult, as most armed groups keep a very low profile, rarely claiming responsibility. In addition, southerners are reluctant to cooperate with police investigations, as they fear they will become the target of revenge attacks.

While information about the militants is scarce, ICG identifies four groups as active. All reportedly share the aim of an independent state.

Most analysts agree the conflict remains driven by local issues. However, if it continues, there are fears the population could become radicalised, attracting international Islamic extremists.

According to an ICG report, "Southern Thailand, Insurgency not Jihad", relations between the southern provinces and the capital during most of the last century were characterised by "harsh assimilation policies, resistance, conciliatory government gestures that were seldom properly implemented, and then an easing of tensions".

Following the annexation of the Patani sultanate at the beginning of the 20th century, the Siam (Thai) government implemented a series of administrative reforms that unseated its ruler and divided the region into three provinces. Local aristocrats were deposed and Thai-speaking officials who reported directly to Bangkok were installed.

At the end of World War Two, the region's hopes of independence and then of accession to British Malaya were dashed. Prime Minister Pridi Banomyong, concerned about rising nationalism, invited Muslim leaders to participate in government and advise the king on Islamic matters.

However, Muslims did not see the new religious bureaucrats as their true representatives, and continued to view the head teachers of ponoh religious boarding schools as their de facto leaders.

In 1946, the modernist Muslim intellectual Haji Sulong, who was head of the provincial Islamic council, petitioned the government for self-rule. A military coup in 1947 led to his imprisonment, causing rebellion to break out across the southern provinces.

Resistance expanded in the 1950s, and by the late 1960s there were more than 60 armed groups operating in the south.

Following two decades of military campaigns against the insurgency waged by these groups, the government adopted a more conciliatory political approach in the early 1980s.

It changed governance and security structures to provide Muslims with wider political participation and economic opportunities. Through the 1980s and into the 1990s, hundreds of fighters accepted amnesty offers and membership of armed organisations shrank. Violence declined significantly.

Yet, in its report on the insurgency, ICG argues that "the very success of the conciliatory approach and the resultant splitting and weakening of the major insurgent groups led to the emergence of new militant strains".

In December 2001, militants carried out five co-ordinated attacks on police posts across the southern provinces - setting the pattern for future violence.

Attacks jumped sharply in 2004, with ministry of interior statistics recording 1,000 insurgency-related incidents in that year, up from 119 in 2003.

Analysts point to three key incidents in 2004. In January, militants carried out co-ordinated attacks - raiding an army weapons' arsenal, torching schools and police posts, and setting off several bombs. The government then imposed martial law.

In April, synchronised attacks were carried out on eleven police posts and army checkpoints across Pattani, Yala and Songkhla. This was followed by a bloody showdown at the Krue Se Mosque in which the Thai army gunned down 32 men. By the end of the day, 105 militants, one civilian and five members of the security forces were dead.

A demonstration in October outside a police station in Tak Bai near the Malaysian border led to the deaths of more than 85 Muslim men and boys. Most died from suffocation after being arrested and stuffed in army trucks for transport to an army base. An enquiry concluded they were not killed deliberately.

ICG identifies two main explanations for the flare-up of violence: the government's dismantling of key institutions in the south, and a watering down of human rights that led local people to lose their faith in the rule of law.

After Thaksin Shinawatra was elected prime minister in 2001, he decided to re-establish top-down political authority over the opposition-controlled southern provinces. As part of that move, he abolished both the Southern Border Provinces Administration Centre and the joint civilian-police-military (CPM) task force.

The closure of the centre removed an important channel through which southerners could express their grievances. With the disbandment of the CPM, control of security and intelligence was handed to the provincial police who were well known for corruption and inefficiency.

With the government's 2003 war on drugs, which heavily affected the south, human rights standards also began to slip. Searches and arrests of suspected Muslim militants increased. Some said they were tortured.

In March 2004, the prominent human rights lawyer Somchai Neelaphaichit disappeared while defending alleged militants who said they had been beaten and tortured while in police custody.

Some two years later, one of the five police officers accused of "disappearing" Somchai was jailed for three years for illegally detaining the lawyer. The others were acquitted. The Asian Human Rights Commission has strongly criticised the government's handling of this case.

In July 2005, the government issued an executive decree that effectively imposed a state of emergency in the southern provinces. Although it was devised as a less harsh alternative to martial law (it included protection against arbitrary detention, for example), it did little to prevent abuses and end impunity for the security forces.

With the decree granting immunity from prosecution for any act committed by officers in the line of duty, its effect was to deepen distrust between Muslims and the authorities.

Shortly afterwards, some 130 Muslims fled across the border to Malaysia to seek asylum. It is thought many more have left the country fearing persecution by the authorities.

Security forces have reportedly begun making efforts to improve relations with local communities, but allegations of arbitrary arrest and brutality remain common.

Meanwhile, small-scale killings have become a feature of everyday life. Those seen as representing the government are major targets - they have included teachers, monks and community leaders, as well as police and soldiers.

A Thai think-tank, Deep South Watch, says 2007 was the bloodiest year so far with 792 people killed, taking the four-year total to 2,776 - a tally compiled from media, police and army reports.

Both Muslims and Buddhists are targeted. Rights groups accuse the authorities of having a hand in some of the killings - a charge they deny.

Sunai Phasuk, a consultant for Human Rights Watch, said the tactic of targeting civilians was intended "to create a climate of fear and to challenge the legitimacy of the administration by showing that it can't protect the population".

He told AlertNet that Muslim southerners felt trapped between both sides, but on balance were more afraid of government security forces. However, the militants are not seen as heroes, he said.

Overall, life has become pretty unpleasant for local people, who say they are afraid to visit markets and tea-shops. A campaign by Muslim militants to ensure that businesses stay closed on Fridays has added inconvenience to fear.

The level of violence during April 2006 snap elections, called by Thaksin amid allegations of corruption and abuse of power, was lower than expected - perhaps because militants knew the government was heading for trouble. The main opposition parties boycotted the poll.

A surprisingly large protest vote against the government forced Thaksin to step down as prime minister shortly afterwards. Three of Thailand's top courts declared the poll result invalid due to the opposition boycott and called new elections.

Seven weeks after stepping aside, Thaksin staged a comeback, and popular discontent with his behaviour grew, particularly among urban voters. In the south - a stronghold of the opposition Democrat Party - he and his Thai Rak Thai (Thais Love Thais) party were already deeply unpopular.

In September 2006, his government was deposed in a bloodless military coup led by Thailand's first Muslim army chief.

Thaksin's removal from power raised hopes that the new government would take a more sympathetic approach to dealing with the southern insurgency.

Soon after Prime Minister Surayad Chulanont was sworn in in October, he visited the south to apologise for the impact of Thaksin's tough policies. He promised more autonomy if the violence were to stop, as well as a role for Islamic sharia law and more development aid.

Yet his gesture has done little to pacify the region. On the contrary, attacks on Buddhist monks and villagers have escalated since November 2006, forcing some to flee their homes.

Militants have targeted schools, torching buildings and shooting teachers, sometimes in front of their pupils. Many schools have been closed.

Thai investigators are also re-examining the possibility that southern militants may have planted bombs in Bangkok that killed three people on New Year's Eve 2006.

Interest seems to be growing in Malaysia in helping find a solution to the unrest in south Thailand. Leaders of the two countries agreed in February 2007 to work together to tackle the roots of the conflict.

In an interview with the Bangkok Post newspaper, Malaysian Prime Minister Datuk Seri Abdullah offered to send spiritual leaders and technology experts to support development of the education system. He said the two states believed "poverty and meagre economic development in the border areas were among the contributing factors which brought about security problems in southern Thailand".

But some analysts argue that unrest in the south cannot be resolved simply by pouring money into economic development projects. "People think they will be exploited by outside businessmen. What they want is to have control over their own lives and how they make a living," ICG's Sunai said.

Since July 2007, security forces have launched frequent raids on suspected insurgent hideouts, detaining dozens of people without charge.

A major problem for politicians in dealing with the militants is that the groups are fluid and secretive.

However, ICG has identified four major groups it says are active:

• BRN-C (Barisan Revolusi Nasional-Coordinate): A faction of the BRN, which was established in the early 1960s to fight for an independent Patani state. It is the largest armed group.
• Pemuda: A youth separatist movement, thought to be responsible for much of the day-to-day violence.
• GMIP (Gerakan Mujahidin Islam Patani): Established by Afghan veterans in 1995 and committed to an independent Islamic state.
• New PULO (Patani United Liberation Organisation): An offshoot of the PULO, which was active in the 1960s-80s. It is the smallest of the armed groups and is fighting for an independent state.

While these groups have all claimed that their goal is an independent state, Sunai believes some elements would be willing to accept a degree of autonomy or even more equitable political participation.

In January 2006, Thaksin rejected an offer to negotiate with the PULO, which was made in a media interview by someone claiming to be the group's foreign policy chief.

During Thaksin's rule, there were fears that his hardline stance on southern unrest could push both militants and frustrated civilians into the arms of international Islamic extremists.

Allegations have already been made that some Thai insurgents are members of the Jemaah Islamiah network, often described as the southeast Asian branch of al Qaeda.

So far any evidence of a connection remains flimsy, and most analysts agree that the conflict has not yet been hijacked by international extremists. But the prospect of this happening is growing.

"The government crackdown on southerners is seen by some as a crackdown on Islam, which is very dangerous," Sunai said. "If the Thai government continues to make mistakes, then one day it's quite possible that extremists could come to Thailand and convince people, where before they have failed."

There have been reports that external extremist organisations may be preparing to get involved in the southern Thailand insurgency, as has occurred in Chechnya and Kashmir.

Although most Thai Muslims do not want the conflict to escalate into a religious war, the government's failure to redress human rights abuses, together with political neglect, continues to boost resentment towards Bangkok.

In a 2005 report on the insurgency, ICG argued that if grievances mount and the conflict escalates, Thai militants could look for outside support or accept unsolicited offers of help from external jihadist groups.

"If such elements enter the fray, we could begin to see either more technically proficient insurgents, or the transformation of a low-level, ethno-nationalist insurgency into something more resembling a regional jihad," it warned.