Where is the media hoopla over this? Are innocent Pakistanis killed by Iranians worth less than innocent Pakistanis killed by the Americans? We have a hypocritical relationship with the US, but far too often we let Iran get away with actions that show a disregard for Pakistan in the name of a false sense of Muslim brotherhood.
Iranians must provide a reason and it may end up being perfectly logical, but if not, they must apologize...and no, blaming it on an Israeli conspiracy does not count. The great relations we enjoyed with the Shah-era Iran is long gone, but nostalgia prevents us from distancing ourselves from a nation that often couldn't care less about us or our interests.