Related Rule
South Africa
Practice Relating to Rule 71. Weapons That Are by Nature Indiscriminate
South Africa’s Revised Civic Education Manual (2004) states: “Weapons which are likely to … affect both civilians and combatants, without distinction, and whose harmful effects go beyond control, in time or place, are illegal per se.” 
South Africa, Revised Civic Education Manual, South African National Defence Force, 2004, Chapter 4, § 56(f).
South Africa’s ICC Act (2002) reproduces the war crimes listed in the 1998 ICC Statute, including in international armed conflicts:
employing weapons, projectiles and material and methods of warfare … which are inherently indiscriminate in violation of the international law of armed conflict, provided that such weapons, projectiles and material and methods of warfare are the subject of a comprehensive prohibition and are included in an annex to the [1998 ICC] Statute by an amendment in accordance with the relevant provisions set out in Articles 121 and 123 of the Statute. 
South Africa, ICC Act, 2002, Schedule 1, Part 3, § (b)(xx).
In its report on “gross violations of human rights” committed between 1960 and 1993, the South African Truth and Reconciliation Commission noted that the killing of more than 600 people in a attack on the South Western Africa People’s Organisation (SWAPO) base/refugee camp at Kassinga in Angola in 1978 constituted a violation of IHL, stating:
International humanitarian law stipulates that the right of parties in a conflict to adopt means of injuring the enemy is not unlimited and that a distinction must at all times be made between persons taking part in hostilities and civilians, with the latter being spared as much as possible. 
South Africa, Truth and Reconciliation Commission Report, 1998, Vol. 2, pp. 52–55, §§ 44–45.