The outlawed National Democratic Front of Bodoland suffered a major setback on Wednesday when two of its top leaders were arrested by the Kolkata police a day after they had collected at least Rs 10 lakh from various businessmen with interests in Assam.

The Kolkata police detective department, which made the arrests, identified the Bodo militants as Sunil Brahma and David Waris. Brahma is a former 'organising secretary' of the NDFB and in charge of its bases in Meghalaya, West Bengal, Jharkhand and Sikkim. His accomplice, who had been operating under the names Bedhung Basumatari, Indra Mohan and P Butlang, is a 'captain' in the NDFB hierarchy.

This is the second time senior NDFB leaders have been arrested outside Assam. On January 1, NDFB vice-chairman Dhiren Boro was arrested in Gangtok. The NDFB mainly operates in western and northern Assam.

Assam police sources in Guwahati said a Special Operations Unit team will arrive in Kolkata on Thursday to interrogate the rebels. The militants, who were arrested from a hotel, had Rs 10 lakh in cash with them. 'This money was collected from different business houses in the past two days,' police officers were quoted as saying in Kolkata newspapers.

The police are trying to find out which business houses paid money to the NDFB. 'We will compile a list of those who are helping these militants. We have some leads and a clear picture will emerge within a few days,' Deputy Commissioner of Police Soumen Mitra, who is in charge of the detective department, was quoted as saying.

The two rebels were produced in a Sealdah court and remanded in police custody till May 6.

In Guwahati Special Branch sources said the two men had flown to Kolkata on Monday from Nagaland's commercial capital Dimapur and were planning to leave Kolkata on Thursday. "This arrest has been made possible by the the combined effort of the Nagaland, Assam and West Bengal police besides other intelligence agencies," top police officials told rediff.com in Guwahati.