A new crisis in relations between Islamabad and Washington was triggered by the recent US tactical escalation from drones to helicopters for destroying insurgent and terrorist concentrations in Pakistan's North Waziristan province, DEBKAfilereports. Pakistan had accepted the drone attacks but, even after they were nearly doubled to 21 this month, the unmanned aircraft were not up to their mission - especially against the most effective Taliban force, the Haqqani network.