Security expert and former CIA officer Robert Baer told the BBC's World Today programme he believed the the latest threat to the West may be linked to the US-led attacks on Haqqaniinsurgents - allies of the Taliban in Waziristan.
Suspicions that the Haqqani network was responsible for the attacks were bolstered by the capture of three insurgents in Kabul on Sunday afternoon who Afghan intelligence officials said had confessed to being members of the Haqqani network who were preparing to assassinate Abdul Karim Khalili, one of Afghanistan's two vice presidents.
Most believe that it has little reason now to turn on the Taliban and the Haqqani networks, given that the Afghan war seems to be reaching an end-game which could give the insurgents some measure of power.