Соответствующая норма
Mexico
Practice Relating to Rule 3. Definition of Combatants
Mexico’s Army and Air Force Manual (2009), in a section on the 1949 Geneva Convention III, states: “The general principle is that any member of the armed forces of a party to the conflict is a combatant”. 
Mexico, Manual de Derecho Internacional Humanitario para el Ejército y la Fuerza Área Mexicanos, Ministry of National Defence, June 2009, § 138.
The manual also states:
375. Status of lawful combatants. The law of war only authorizes certain groups of people to engage in military operations, and these operations may only be directed against certain groups of people. The legitimate agents and objects of acts of war are included under the term lawful belligerents or combatants.
376. According to article 2 of the [1907 Hague] Regulations concerning the Laws and Customs of War on Land, the following categories are considered combatants:
A. Militia and volunteer corps fulfilling the following conditions:
a. they are commanded by a person responsible for his subordinates;
b. they have a fixed distinctive emblem recognizable at a distance;
c. they carry arms openly;
d. they conduct their operations in accordance with the laws and customs of war.
B. Those taking part in a levée en masse, which occurs when:
a. the inhabitants of a territory which has not been occupied, on the approach of the enemy, spontaneously take up arms to resist the invading troops;
b. they are regarded as “belligerents” if they carry arms openly and respect the law of war.
377. Under the First Geneva Convention of 12 August 1949, the following are considered combatants:
A. Organized resistance movements, even if the territory is occupied, provided that they fulfil the following conditions:
a. they are commanded by a person responsible for his subordinates;
b. they have a fixed distinctive sign recognizable at a distance;
c. they carry arms openly;
d. they conduct their operations in accordance with the laws and customs of war.
B. Members of the regular armed forces of a government. 
Mexico, Manual de Derecho Internacional Humanitario para el Ejército y la Fuerza Área Mexicanos, Ministry of National Defence, June 2009, §§ 375–377(A)–(B).
Mexico’s IHL Guidelines (2009) states: “Combatants are the members of the armed forces of a party to the conflict and the members of militias and volunteer corps forming part of such armed forces.” 
Mexico, Cartilla de Derecho Internacional Humanitario, Ministry of National Defence, 2009, § 3.
(emphasis in original)