Guerrilla (Spanish for "little war") warfare is employed by small groups of combatants, who use harassment and terror against regular armies. Guerilla fighters specialize in ambushes, raids, and mobility, and often rely on local civilians (whether willing or not) to aid them with their operations. Guerilla tactics were effectively used worldwide during the 20th and 21st century, for example by Mao Zedong in China, Fidel Castro in Cuba, and Dzhokhar Dudaev in Chechnya - among many others.