A top police official said today that the four ISI mercenaries had admitted during interrogation that they were sent to Assam with specific assignments. `Their first task was to make arrangements to send explosives to the state through Bangladesh for insurgent groups operating in north-eastern region and Jammu and Kashmir,' he told UNI here.

The official termed as a `big achievement' the recovery of 30 kg RDX from a specified place inside Bangladesh across the West Bengal border on Saturday night by Assam and West Bengal police.