Insurgencies fall into the category of "irregular warfare", since an insurgency normally lacks the organization of a revolution, even though it has the same aims. Revolutions often begin within a country's armed forces, whereas insurgencies often arise in remote areas, where they gain strength slowly by winning the confidence of rural populations. An insurgency may be based on ethnic or religious identity, or its roots may be basically political or economic. Since insurgencies are rarely strong enough to face a national army head-on, insurgents (often called guerrillas) tend to use such tactics as bombing, kidnapping, hostage taking, and hijacking.