While Iran's electoral paroxysm captured the world's attention, the simmering of ethnic tension in what many people often perceive to be a monolithic state continued unabated. Only a little more than 50% of Iran's population is Persian; the rest is composed of several other ethnic groups. In recent years, Iran has faced persistent attacks allegedly perpetrated by anti-government elements of the Kurdish, Azeri and Baluchi minorities, among others, who maintain that they face discrimination despite a constitutional guarantee of rights. The Islamic Republic, ruled by a Shi'ite theocracy, has staged mass arrests and put to death dozens of "traitors and criminals." Still, the unrest escalated: in October, a suicide bombing by the minority Sunni group Jundullah killed dozens of people including at least five commanders of Iran's Revolutionary Guards and left dozens of others wounded, the deadliest insurgent strike to that point. Tehran accused the U.S. and Britain of stoking the fire; both countries denied it.