By Subir Bhaumik BBC reporter in Calcutta

Police in India's north-eastern state of Assam say they have arrested one of the state's top separatist leaders.

Bodos make up 13% of Assam's population

Govinda Basumatary was arrested at a railway station in central Assam as he was about to board a train for Calcutta, a senior police official told the BBC.

Mr Basumatary was the general secretary of the outlawed National Democratic Front of Bodoland (NDFB), the stronger of the two rebel groups representing the Bodo tribe.

The Bodos have been fighting for a separate homeland for the last 20 years.

Secrets

The intelligence chief of Assam police, Khagen Sarmah, told the BBC that Mr Basumatary had entered the state from one of the group's bases in southern Bhutan last week, and was trying to fly out to Bangkok from Calcutta.

He said a rail ticket for Calcutta was recovered from the rebel leader after his arrest at Rangiya railway station, just before midnight.

Mr Basumatary is being questioned by the Assam police and Mr Sarmah said he is likely to provide a lot of details about the activities of his group.

Rebel rift

The other Bodo rebel group, the Bodoland Liberation Tiger Force (BLTF) says it is close to a final settlement with the government.

But the NDFB says it plans to continue its fight for independence.

In recent weeks, its guerrillas have launched a number of attacks on Indian security forces, as well as members of the rival BLTF.

Non-Bodo people living in Bodo-dominated areas have also been targeted, in an attempt to scuttle a possible settlement to the Bodo problem.