Two top militants of the banned National Democratic Front of Bodoland were arrested in Kolkata on Wednesday.

The duo was identified as Sunil Brahma and David Waris. Brahma is a former organising secretary of the NDFB and in charge of the outfit's bases in Meghalaya, West Bengal, Jharkhand and Sikkim. David, who had been operating under the names of Bedhung Basumatari, Indra Mohan and P Butlang, is a captain.

The Kolkata police arrested the leaders a day after they had collected at least Rs 1 million from various businessmen with interests in Assam.

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

In Guwahati, special branch sources said the two had flown in to Kolkata on Monday from Dimapur in Nagaland and were planning to leave Kolkata on Thursday.

"This arrest has been made possible by the combined effort of the Nagaland, Assam and West Bengal police, besides other intelligence agencies," Sharma said.

The Assam police team, armed with fresh arrests warrants issued by courts in Assam, reached Kolkata on Thursday and will bring back the militants after their judicial custody ends, IGP Special Branch Khagen Sarma said in Guwahati. At least a dozen cases have been registered against the two in Assam, he added.

This is the second time that senior leaders of the outfit, which operates mainly in western and northern Assam, have been arrested outside the state.

On January 1 this year, NDFB's vice-chairman Dhiren Boro was picked up from Sikkim capital Gangtok.