Islamic extremist groups are organizations that use a radical interpretation of Islam to justify violence and terrorism. They often aim to establish a society governed by their strict interpretation of Sharia law and may target civilians, governments, and other groups they view as enemies. These groups can vary in size and influence, with some, like Al-Qaeda and ISIS, gaining international notoriety. They often recruit members through propaganda and exploit political instability in regions where they operate, leading to significant security challenges for affected countries and the global community.