Guwahati, March 1 : The banned National Democratic Front of Boroland (NDFB) has embarked on a massive extortion drive here, asking businessmen to cough up huge sums of money to fill its coffers. The extortion notes have been served in the past three weeks mostly to businessmen from the Fancy Bazar locality, the heart of trading in the Northeast. Traders have been warned of dire consequences if they did not assist the ?revolutionary goal,? intelligence sources said. The sources said the rebels have set deadlines ranging from three weeks to a month for the fulfilment of their demand for funds ranging from Rs 5 lakh to a crore. Though this is not the first time that the NDFB has targeted the business community here, the number of extortion notes served ?is certainly higher? this time, they added. Additional superintendent of police (city) J.C. Barman confirmed that the NDFB had served extortion notes on a number of businessmen in the city. ?They have received the demands in the last few weeks but none of them has reported the matter to the police so far,? he said. In the absence of formal complaints by the extortion victims, the police are finding it difficult to take action. ?However, we have chalked out an alternative plan of action to curb this menace and apprehend the victims,? Barman said. Apart from facing a severe funds crunch, the NDFB is also facing an ?urgent need to upgrade its fire power,? to carry on its subversive activities in the face of Army operations in the state, the sources said. The NDFB had given several crores of rupees to another rebel outfit for a large consignment of sophisticated arms and ammunition. But this consignment was not delivered to the Bodo outfit, landing it in a difficult position, sources said. Moreover, the counter-insurgency operations in the state, which have produced ?good results? in the past year, have virtually cut off the outfit?s funds flow, the sources claimed. The reluctance of the tea majors to pay the outfit after the Tata Tea incident has compounded its problems, the sources said, adding, ?Even then, we are keeping a strict vigil on certain tea companies which may still be aiding the militants financially. Meanwhile, a large number of NDFB militants as well as rebels of other outfits like the United Liberation Front of Asom, have infiltrated into the city, sources said. The police have arrested some of them over the last few weeks after conducting several raids here and in the neighbouring areas. The police have also recovered sophisticated devices like remote-controlled battery chargers.