One of the outstanding sources of resistance to imperial power in the Muslim world came from Sufi groups. While Sufi brotherhoods are generally known for a more quietist and mystic approach to Islam, they traditionally rank among the best organized and most coherent groupings in society. They constitute ready-made organizations - social-based NGOs, if you will - for maintaining Islamic culture and practices under periods of extreme oppression and for fomenting resistance and guerrilla warfare against foreign occupation. The history of Sufi participation in dozens of liberation struggles is long and widespread across Asia, the Middle East, and Africa. Sufi groups were prominent in the anti-Soviet resistance, and later against the American in Afghanistan and against US occupation forces in Iraq.