In international humanitarian law and international criminal law, an indiscriminate attack is a military attack that fails to distinguish between legitimate military targets and protected persons. Indiscriminate attacks strike both legitimate military and protected objects alike, thus violating the principle of distinction between combatants and protected civilians. They differ from direct (or deliberate) attacks against protected civilians and encompass cases in which the perpetrators are indifferent as to the nature of the target, cases in which the perpetrators use tactics or weapons that are inherently indiscriminate (e.g., cluster munitions, anti-personnel mines, nuclear weapons), and cases in which the attack is disproportionate, because it is likely to cause excessive protected civilian casualties and damages to protected objects.
Indiscriminate attacks are prohibited both by the Geneva Conventions Additional Protocol I (1977) and by customary international humanitarian law. They constitute a war crime under the Rome Statute of the International Criminal Court, and the perpetrators can be prosecuted and held responsible in international and domestic courts.