There's no way that was Mossad or the US. There
may be some backing for members of anti government forces in Iran. But this was done by Iranian members of anti Shia rule forces.
Here's a link
Wikipedia to some info on the domestic unrest currently under way in Iran. Some people even protesting for the return of the Shah. Shah Pahlavi died in 1980 so I'm not sure what they mean; maybe a return to a constitutional monarchy under his son (now in exile).
If a professional state backed assassination was attempted they would have just blown up the car or planned a hit at the place where he was due to enter or exit the vehicle. There's no way operatives would attempt it with 12 gunmen. We have no way to verify the Iranian story either. It may be complete bs, hyped up to
appear to have been executed by a state actor.
It is common for dictators to draw on fear of foreign forces when there is discord in their nation. Whenever the economy went to crap or there was a political scandal in Argentina, the government would start propaganda about the "Malvinas." They even tried invading the islands at one point.
The Iranian press is cooking up a distraction to take steam away from anti Theocracy forces in their own nation, nothing more. It is even possible they killed the guy themselves if they thought he was turning against them.
If you get bored and have the time here's a good movie on
You Tube