 Tens of thousands of Afghan refugee children in Pakistan were educated in madrassas "in a spirit of conservatism and religious rigor", and went on to fill the ranks and leadership of the Taliban in Afghanistan and Sipah-e-Sahaba in Pakistan.The groups embodied new varieties of Political Islam – "Salafi jihadism" among the foreign volunteers, and a "hybrid" Deobandi jihadism among the madrassa-educated.President Najibullah, before his ouster by the mujahideen in 1992, told a visiting US academic that "Afghanistan in extremist hands would be a center of instability."