Military regimes favoring Islamic-oriented governments have dominated national politics since independence from the UK in 1956. Sudan was embroiled in two prolonged civil wars during most of the remainder of the 20th century. These conflicts were rooted in northern economic, political, and social domination of largely non-Muslim, non-Arab southern Sudanese. The first civil war ended in 1972 but broke out again in 1983. The second war and famine-related effects resulted in more than four million people displaced and, according to rebel estimates, more than two million deaths over a period of two decades. Peace talks gained momentum in 2002-04 with the signing of several accords. The final North/South Comprehensive Peace Agreement (CPA), signed in January 2005, granted the southern rebels autonomy for six years followed by a referendum on independence for Southern Sudan. The referendum was held in January 2011 and indicated overwhelming support for independence. A separate conflict, which broke out in the western region of Darfur in 2003, has displaced nearly two million people and caused an estimated 200,000 to 400,000 deaths. The UN took command of the Darfur peacekeeping operation from the African Union in December 2007. Peacekeeping troops have struggled to stabilize the situation, which has become increasingly regional in scope and has brought instability to eastern Chad. Sudan also has faced large refugee influxes from neighboring countries primarily Ethiopia and Chad. Armed conflict, poor transport infrastructure, and lack of government support have chronically obstructed the provision of humanitarian assistance to affected populations.