Related Rule
Practice Relating to Rule 12. Definition of Indiscriminate Attacks
In its written statement submitted to the ICJ in the Nuclear Weapons (WHO) case in 1995, Nauru invoked the rule of international law that prohibits the use of weapons which “cannot distinguish between civilian objects and military objectives”. 
Nauru, Written statement submitted to the ICJ, Nuclear Weapons (WHO) case, 15 June 1995, pp. 19–20.