Related Rule
Spain
Practice Relating to Rule 12. Definition of Indiscriminate Attacks
Section A. Attacks which are not directed at a specific military objective
Spain’s LOAC Manual (1996) states: “ Indiscriminate attacks are those … which are not directed at a specific military objective”. 
Spain, Orientaciones. El Derecho de los Conflictos Armados, Publicación OR7-004, 2 Tomos, aprobado por el Estado Mayor del Ejército, División de Operaciones, 18 March 1996, Vol. I, § 4.4.c.
Spain’s LOAC Manual (2007) includes in its definition of indiscriminate attacks “attacks that are not directed at a specific military objective”. 
Spain, Orientaciones. El Derecho de los Conflictos Armados, Tomo 1, Publicación OR7–004, (Edición Segunda), Mando de Adiestramiento y Doctrina, Dirección de Doctrina, Orgánica y Materiales, 2 November 2007, § 4.4.c.