A border dispute over grazing rights between Mauritania and Senegal in April 1989 set off communal violence in Nouakchott and Dakar that left hundreds dead. Mauritania's government used the crisis to expel tens of thousands of its own black citizens, chiefly Halpulaar (Peul), Soninke, Wolof and Bambara people from the Senegal River valley: Human Rights Watch reported that they were summoned, forced to give up their identity cards, trucked to the river and pushed across, while villages were burned and possessions and livestock seized. Expulsions continued into 1990, and between November 1990 and March 1991 Africa Watch reported that 500-600 black political prisoners, mostly Halpulaar soldiers and civil servants, were executed or tortured to death in custody. Human Rights Watch described the campaign as serving the government's 'Arabization' of the country. Some 35,000 refugees returned on their own in 1996-98, and from January 2008 UNHCR ran an organised repatriation from Senegal that was declared complete in March 2012, though returnees protested that farmland confiscated in 1989 had not been restored and many struggled to re-establish their identity documents.
Mauritania's military government expelled tens of thousands of black Mauritanians, mainly Halpulaar (Peul), Soninke and Wolof from the Senegal River valley, across the border into Senegal and Mali, stripping them of identity papers and property
This is a documented minimum, and the upper bound is deliberately left open. Africa Watch (Human Rights Watch World Report 1992) reported that 500-600 black political prisoners were executed or tortured to death in custody between November 1990 and March 1991, with a preliminary list naming 173; these deaths are counted because they were part of the same campaign against the black population. Human Rights Watch also documented a pattern of killings by the army and militias in the Senegal River valley in 1990-91 that it could not quantify, and reported two people suffocating during deportation. The hundreds killed in the April 1989 communal violence in Nouakchott and Dakar, many of them Senegalese, are not included.
Human Rights Watch / Africa Watch World Reports for 1989-1992 documented massacres by authority-organised bands in April 1989, the confiscation and destruction of identity cards, the burning of villages and seizure of livestock, the mass arrest, torture and execution of black detainees in 1990-91, and indiscriminate killing, torture and rape in the Senegal River valley.
Mauritania, Senegal, Mali