Opening fire and Returning fire refers to the first shots fired in an engagement. It can be small arms fire or artillery. The side that "opens fire" is the first to shoot. This has ethical and often legal or political implications (see aggression, first strike). The side that returns fire does so in response to opening fire. The ethical and legal rules for returning fire are different (see self-defense).
In confrontations between US military forces and civilians, there are strict ethical and legal rules of engagement applied to the military. The question Who fired the first shot? has legal and ethical implications.
- Kent State protests - shot "heard"?
- Waco incident - tank fires on religious compound
- Fallujah incident - dispute over who shot first
- My Lai - unarmed civilians massacred
- Boston Massacre - British soldiers shoot at colonists armed with... snowballs