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Rwanda
Practice Relating to Rule 14. Proportionality in Attack
Rwanda’s Law Repressing the Crime of Genocide, Crimes against Humanity and War Crimes (2003) provides:
Article: 8
A war crime is one of the following acts, committed during armed conflicts against persons or property protected under the Geneva Conventions of 12 August 1949 and its Additional Protocols I and II of 8 June 1977:
9° launching a deliberate attack against the civilian population or against its objects, in the knowledge that such attack will cause loss of life or injury or grave damage to their objects, which would be judged as excessive in relation to the military advantage anticipated;
Article: 9
Shall be punished by one of the following penalties any person having committed one of the war crimes provided for in Article 8 of this law:
1° the death penalty or life imprisonment where he has committed a crime provided for in point 1°, 2°, 3°, 9°, 11° or 16° of Article 8 of this law. 
Rwanda, Law Repressing the Crime of Genocide, Crimes against Humanity and War Crimes, 2003, Articles 8–9.
On 22 April 1995, between 200 and 300 people died in a camp for internally displaced persons in Kibeho in Rwanda. The Rwandan President stated that these deaths were the result of
the same machetes of those who committed the genocide and the massacres. Others were killed during shootings in self-defence by the governmental armed forces and by MINUAR in response to attacks launched by the Interahamwe militia located in the camp of Kibeho. 
Rwanda, Declaration by the President concerning the decision to close the IDP camps of Gikongoro, Kigali, 24 April 1995, p. 2, Report on the Practice of Rwanda, 1997, Chapter 1.5.
An international commission investigating the events of Kibeho considered that by using automatic guns and heavier weapons, such as grenades and rocket-launchers, against persons who carried guns and traditional weapons, such as machetes and stones, the Rwandan army had acted disproportionately. 
Rapport de la Commission Internationale d’Enquête Indépendante sur les événements de Kibeho, April 1995, pp. 9–10, Report on the Practice of Rwanda, 1997, Chapter 1.5.
Since no official statement denied this alleged violation of the principle of proportionality in attack, the Report on the Practice of Rwanda concludes that Rwandan practice implicitly confirms the existence of such a norm. 
Report on the Practice of Rwanda, 1997, Chapter 1.5.