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Peru
Practice Relating to Rule 7. The Principle of Distinction between Civilian Objects and Military Objectives
Section E. Attacks against civilian means of transportation
Peru’s IHL Manual (2004) states:
(a) Enemy merchant vessels
(1) Enemy merchant vessels may only be attacked if they meet the definition of a military objective.
(3) Any attack on these vessels must comply with the basic rules of international humanitarian law, the requirement to distinguish between protected persons and objects and military objectives and the conditions that must be met for an object to be considered a military objective.
(b) Enemy civil aircraft
(1) Enemy civil aircraft may only be attacked if they meet the definition of a military objective.
(3) Any attack on these aircraft must comply with the basic rules of international humanitarian law, the requirement to distinguish between protected persons and objects and military objectives and the conditions that must be met for an object to be considered a military objective. 
Peru, Manual de Derecho Internacional Humanitario para las Fuerzas Armadas, Resolución Ministerial Nº 1394-2004-DE/CCFFAA/CDIH-FFAA, Lima, 1 December 2004, § 130.a.(1) and (3) and b.(1) and (3).
Peru’s IHL and Human Rights Manual (2010) states:
120. Enemy vessels and aircraft which benefit from immunity against attack
a. The following classes of enemy vessels cannot be attacked:
(5) Passenger ships if they only transport civilian passengers.
121. Other enemy vessels and aircraft
a. Enemy merchant vessels
(1) Enemy merchant vessels may only be attacked if they meet the definition of a military objective.
b. Enemy civil aircraft
(1) Enemy civil aircraft may only be attacked if they meet the definition of a military objective.
(3) Any attack on these aircraft must comply with the basic rules of International Humanitarian Law (IHL), the requirement to distinguish between protected persons and objects and military objectives and the conditions that must be met for an object to be considered a military objective. 
Peru, Manual de Derecho Internacional Humanitario y Derechos Humanos para las Fuerzas Armadas, Resolución Ministerial No. 049-2010/DE/VPD, Lima, 21 May 2010, § 120(a)(5), p. 310, § 121(a)(1), p. 312, and § 121(b)(1) and (3), p. 313.
The Report on the Practice of Peru refers to a scholar who wrote that in 1879, during a conflict against Chile, a Peruvian admiral refused, on humanitarian grounds, to attack an enemy vessel that he believed to be a transport ship. 
Report on the Practice of Peru, 1998, Chapter 1.3, referring to E. Angeles Figueroa, El Derecho Internacional Humanitario y los Conflictos Armados, Lima, 1992, pp. 119–120.