Members of Thailand's minority Muslim community - based almost exclusively in the country's southern provinces - have been at loggerheads with Bangkok for decades.
Thailand's Muslims often complain of discrimination and a lack of opportunities, a resentment which occasionally leads to clashes with the authorities.
More than 100 people died in one day of violence in April
But in January 2004, a wave of attacks sparked increased violence in the south, which has seem more than 800 people die since.
Analysts say police corruption, drug running and theft by local criminal gangs have often been responsible for the violence.
But there is an increasing suspicion that Islamic separatists - perhaps allied to international militant groups such as Jemaah Islamiah - are behind the attacks.
Thailand's Muslims are largely concentrated in the four southern provinces of Narathiwat, Pattani, Songhkla and Yala.
The area is less prosperous than central Thailand, and many of the region's inhabitants complain they are at a disadvantage compared to the country's Buddhist majority.
But those living in the region are also very different from the rest of the Thai population.
The southern provinces were originally part of the ancient Kingdom of Pattani, a
semi-autonomous Malay region which adopted Islam in the mid-13th century.
Thailand annexed the region in 1902, but the people living there had - and still do have - far more in common with their neighbours in Malaysia.
They speak Yawi, a Malay dialect, and most importantly they are Muslims, abiding by Islamic rules and restrictions.
Increasingly estranged from the Bangkok government, Muslim separatists began an insurgency in the 1970s.
The violence eventually died down in the 1990s - but only after the government promised to channel more funds into the region and ensure the Muslim community an adequate political representation.
A raid on an army depot in January 2004 signalled a return to the violence.
Four soldiers were killed and 400 guns, most of them M-16 rifles, were stolen from a store in Narathiwat province.
Since then there have been frequent incidents in which symbols of authority - including police officers, teachers and Buddhist monks - have been targeted by Muslim gunmen.
The deadliest incident happened on 28 April, when hundreds of suspected Islamic militants launched a series of raids on security posts in the region.
The day ended in the massacre of more than 100 of the poorly-armed militants, and there was international concern over the degree of force used by security personnel.
Another bloody incident took place in the southern district of Takbai in October.
More than 80 people died after a protest turned violent, Seven were killed at the scene and 78 died in army custody from suffocation, after being loaded into army trucks.
Links to radical groups
The Thai government continues to insist that most of the attacks in the south can be attributed to local criminals.
But it seems evident that organised Islamic separatist groups are playing at least a part in the violence.
There are a number of Muslim separatist groups known to operate in southern Thailand - including Pulo (the Pattani United Liberation Organisation), BRN (the Barisan Revolusi Nasional) and GMIP (Gerakan Mujahadeen Islam Pattani).
In the past, these groups have been linked to larger Islamic organisations such as Jemaah Islamiah - blamed for terrorist attacks across South East Asia - and the Free Aceh Movement (GAM) in the troubled Indonesian province of Aceh.
No group has categorically claimed responsibility for recent attacks, and it remains difficult to be certain who is ultimately behind the upsurge in violence.
But one thing seems certain. If police and security personnel continue to act with such heavy-handed methods, the animosity between them and the Muslim inhabitants of southern Thailand is only likely to increase.