A couple of days ago we reported that Blizzard players in Iran were unable to connect to the BattleNet service for World of Warcraft. According to Blizzard who have looked into this further, the blocking is because of US sanctions against Iran.
A further post from Blizzard today explains the situation:
Our team has been watching this thread closely, and we understand the desire for more information about this situation. Blizzard Entertainment cannot speak to any reports surrounding the Iranian government restricting games from its citizens.
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.
Whether the the Iranian government issued their ban on a plethora of titles on the back of these sanctions is unclear, but it looks like Iranian gamers are out of luck.