"Guerrillas who follow the rules spelled out in the Geneva Conventions are considered to have combatant status and have some of the same rights as regular members of the armed forces.

In international conflicts, guerrillas must distinguish themselves from the civilian population if they are preparing or engaged in an attack. At a minimum, guerrillas must carry their arms openly. (Protocol I, Art. 44, Sec. 3)

Under the earlier Geneva Conventions, which are more widely recognized, a guerrilla army must have a well-defined chain of command, be clearly distinguishable from the civilian population, carry arms openly and observe the laws of war. (Convention III, Art. 4, Sec. 2)

http://www.genevaconventions.org/


In the case of an internal conflict, combatants must show humane treatment to civilians and enemies who have been wounded or who have surrendered. Murder, hostage-taking and extrajudicial executions are all forbidden. (Convention I, Art. 3)"