Having earlier believed that it was Iran's fault gamers in the Middle-Eastern nation had suddenly found themselves unable to access Blizzard's World of Warcraft and Diablo III, it turns out there's another country's government to blame. Namely, that of the United States.
Because the US has imposed trade restrictions and economic sanctions on the Islamic Republic, most American companies aren't allowed to do business in the country. By selling games and subscriptions to Iranian residents online, Blizzard had been doing business in Iran, and apparently that had to stop.
The publisher issued a statement over the weekend which reads:
This also prevents us from providing any refunds, credits, transfers, or other service options to accounts in these countries. We apologize for any inconvenience this causes and will happily lift these restrictions as soon as US law allows.