Assam has been plagued by violence since the 1970s
Indian security forces have been fighting separatist rebels in the state of Assam for decades. Who is behind the violence and what are the prospects for peace? BBC News looks at the background to one of India's longest-running insurgencies.
Why is there so much violence in Assam?
Much of the recent trouble in Assam has been blamed by the authorities on the United Liberation Front of Assam (Ulfa), formed in 1979 to fight for the state's independence. It has carried out a series of campaigns, including targeting oil and gas pipelines, transport and telecommunication facilities and security patrols.
At least 10,000 people have died since 1979. There are other less powerful insurgent groups in Assam but they have mostly reached negotiated agreements with the authorities.
What are the chances of bringing Ulfa to the negotiating table?
Negotiations with the Ulfa broke down in late 2006 after running for about a year. The BBC's Subir Bhaumik says the chances of re-starting the talks are slim.
Is Ulfa united?
Some members of the separatist group - including one of its elite strike battalions - have laid down their arms and are in active discussions with the government. But two battalions allegedly led by the central Ulfa leadership from secret hideouts in neighbouring Bangladesh remain committed to an armed struggle.
What is the strategy of the Indian government?
The government has tried to split the Ulfa - hence its deal with members of the so-called 28th battalion. But members of two other Ulfa battalions - the 27th and 109th - did not reach a deal which prompted the army to intensify its operations against them. The Indian government says that they too must shun violence and agree to direct negotiations if they are also to be brought into the peace process.
What is the strategy of Ulfa?
Ulfa says that the army must stop military operations and release members of its top leadership from military custody before it enters negotiations. Military analysts say that with its support base dwindling, the Ulfa has resorted to "urban terrorism" as the only way to strike back.
What will happen now?
Some experts fear that Assam is now entering another dark period - bomb explosions followed by military clampdowns - which have over the years seriously inhibited economic growth in a state which is only connected to the rest of India by a narrow but strategically important strip of land known as the "chicken neck".
Is there an ethnic dimension to Assam's troubles?
Assam is an ethnically diverse state. Only about one-third of the population are ethnic Assamese. The rest are migrants - from elsewhere in India or from what is now Bangladesh - while about a quarter of the people are ethnic tribesmen. They resent assimilation into mainstream Assamese society and want a separate homeland of their own. Muslim migrants in particular have increasingly come under attack from the Assamese and from indigenous tribesmen. They were targeted during recent riots in October and are now threatening to assert their Bengali linguistic roots. If they join up with Bengali Hindus, it will be Bengali - and not Assamese - which will become the language of the majority in Assam.
So is the violence two-tiered?
Yes. On the one hand there are the attacks against the migrants - especially Bengali Hindus - who are seen as competitors for jobs and educational opportunities. Increased Assamese insecurity was the driving force behind the six-year anti-migrant movement (1979-85) that led to more than 3,000 deaths in riots and firing by police. On the other hand the state has for decades been the centre of a violent Assamese insurgency - initially targeted at migrants but now clearly separatist with demands to break away from India. That combined with the activities of smaller tribal insurgent groups has prompted Assam's best known social scientist, Sanjib Baruah, to call the state a "zone of durable disorder".
How dangerous is this for the future?
It's potentially explosive. The Assamese are now very sensitive about the migrant question. They fear that one day they will become "foreigners in their own land". In the neighbouring state of Tripura migrants from Bangladesh are now in the majority - indigenous tribesmen constitute less than 30% of the population. This explains why the Assamese have time and again hit out at migrants. A similar pattern has emerged elsewhere in India, such as in the western state of Maharashtra where violence against migrant workers has spiralled this year.