In 1976, when Mauritanian troops occupied the Western Sahara province of Tiris al Gharbiyya, as per terms of the Madrid Agreements, they were immediately challenged in fierce fighting with Polisario guerrillas. The fighting would drag on for two years, draining an already improvised economy, provoking ethnic conflict, and causing large numbers of casualties. The direct cost of Mauritania's colonial venture proved exorbitant. Mauritania rapidly increased its armed forces from only 3,000 at the beginning of 1976 to about 12,000 at the beginning of 1977 by mid-1978 the Mauritanian armed forces numbered between 15,000 and 17,000. Between 1975 and 1977, the government's expenditures increased by 64 percent, most of which was allotted for defense (see Defense Budget and the Economy , ch. 5). This military buildup placed a heavy burden on the weak economy and diverted funds badly needed development projects. Further alienating the population was a special defense tax, which the government levied against the entire population despite the tax, the country was on the verge of bankruptcy by late 1977. Moreover, as the war progressed, the power of the Mauritanian military grew, contributing to internal disunity and a weak civilian government unable to solve the problems of nation buildings.

Having more than 6,400 kilometers of undefended borders with Mali and Algeria, Mauritania was highly vulnerable to attacks by Polisario guerrillas, who were armed and supported by Algeria. The government's inability to protect Mauritania's major towns, even Nouakchott, which was attacked in June 1976, raised fears that Moroccan troops would move into Mauritania, ostensibly to interdict the guerrillas but also as an expansionist vanguard. There was also fear of a possible plan on the part of Morocco's enemy, Algeria, to replace the Daddah government with a puppet regime.

Data as of June 1988