GUWAHATI, July 20: Security agencies in the Northeast are on the alert for large numbers of fake currency notes being circulated - strongly believed to be the handiwork of the ISI of Pakistan. In the past few months, police in the region have seized a large number of fake notes from different towns, the biggest haul being reported from Aizawl, the capital of Mizoram. Last month, Aizawl police seized fake Rs 500 denomination currency notes totally Rs 86,500 from two persons arrested from a village on the Mizoram-Manipur border.