Related Rule
Argentina
Practice Relating to Rule 7. The Principle of Distinction between Civilian Objects and Military Objectives
Argentina’s Law of War Manual (1989) provides:
In any armed conflict, the right of the Parties to the conflict to choose methods or means of warfare is not unlimited. Therefore, it is prohibited to employ weapons, projectiles and material and methods of warfare of a nature to cause superfluous injury or unnecessary suffering and, besides, in order to guarantee the protection of the civilian population and civilian objects, the Parties to the conflict shall at all times distinguish between the civilian population and combatants and between civilian objects and military objectives. 
Argentina, Leyes de Guerra, PC-08-01, Público, Edición 1989, Estado Mayor Conjunto de las Fuerzas Armadas, aprobado por Resolución No. 489/89 del Ministerio de Defensa, 23 April 1990, § 4.01 (general principles).
It is reported that, during the War in the South Atlantic, both parties directed their hostile acts only against military objectives. 
Carlos Horacio Cerdá, El respeto del Derecho International Humanitario durante el Dessarollo del Conflicto Armado del Atlántico Sud, Report on the Practice of Argentina, 1997, Chapter 1.3.
Argentina’s Law of War Manual (1989) provides:
4.03 Protection of civilian and civilian objects. The prohibition of attacking civilian persons or civilian objects comprises all acts of violence, whether offensive or defensive. Indiscriminate attacks are included in such prohibition.
4.45 … Objects of a civilian nature shall not be subject to attack nor reprisal. 
Argentina, Leyes de Guerra, PC-08-01, Público, Edición 1989, Estado Mayor Conjunto de las Fuerzas Armadas, aprobado por Resolución No. 489/89 del Ministerio de Defensa, 23 April 1990, §§ 4.03 and 4.45.
Argentina’s Law of War Manual (1989) provides that intentionally attacking civilian objects is a grave breach. 
Argentina, Leyes de Guerra, PC-08-01, Público, Edición 1989, Estado Mayor Conjunto de las Fuerzas Armadas, aprobado por Resolución No. 489/89 del Ministerio de Defensa, 23 April 1990, § 8.03.