Besides Assam border, the ultras were staying along the international border of Arunachal Pradesh and Nagaland and the timing for the strike was so chosen as law and order personnel were primarily engaged in security duty during that period, said intelligence sources, looking after Upper Assam range, including the two states.
Cadres of CPI(Maoist), Paresh Baruah-led ULFA(I), NSCN, United Liberation Council of Arunachal (ULCA) and Tai Ahom Liberation Tiger Force of Asom (TALTFA) were moving along the three border states and serving extortion notes since the last couple of weeks.
Their interrogation revealed that a group of ULFA(I) cadres were undergoing training in the camp to be followed by ULCA cadres.
Money collected by extortion would meet the cost of training in camps of Myanmar and procuring arms and ammunition, they said, adding NSCN was acting as a guide of the other groups as it had got good hold in those areas.
The sources said security forces would strike and crack down on the militants whenever they engage in terrorist activities.