Warfare between different tribal groups, usually within the same 'national' boundary, causes disruption and disunity in the nation. Tribal warfare and conflict have been known to disrupt rural development programmes. This factor comes into play particularly when an extensive development programme takes in several ethnic groups. Since rural development programmes attract strangers into otherwise closely-knit homogenous rural communities, conflicts in morals, manners and of personality often create potentially explosive situations which require the talents of competent social workers to resolve.
Tribal warfare has been recently reported in the Philippines, Burundi, Rwanda, Sudan, and South Africa. According to a 1993 report, nearly 8,000 Zulu tribesmen of the Kwazulu-Natal region in South Africa have been killed as a result of tribal warfare since 1985. Since its independence, clan fighting and killing have erupted periodically between Hutus and Tutsis in Burundi, as in 1969, 1972 (around 300,000 dead), 1988, 1993 and 1994, when it is estimated that at least 100,000 were killed and 700,000 displaced to refugee camps in Rwanda, Tanzania or Zaire. In 1996 in Somalia, more than 9,000 people were driven to flee as a result of clan warfare in the Juba river valley. Following withdrawal of the UN peacekeeping troops in 1995, the country splintered into several parts, each governed by a different clan warlord concerned to increase his territory.