In geopolitical terms the Russian Federation will never allow Iran to become a regional power in the Middle East, thus do not expect any sort of diplomatic breakthrough between the US and the Islamic Republic anytime soon. Either Russia gives the go-ahead to Israel to bomb Iran's nuclear and military infrastructure (and not America as everybody is set to believe) or the unavoidable escalation of the ongoing civil war in Syria will facilitate that. Moscow has lots to win by having a destabilized region (specially a war of attrition between Shias and Sunnis) and oil trade being disrupted in that part of the world. Additionally, it is extremely questionable why the Supreme Leader of Iran hasn't ordered emergency drills to prepare the civilian population of his country to be ready for the massive bombardment that will be carried out by the US, NATO, Israel, and the Arab military alliance...and nuclear ordnance will be used this time.
from the article: Iranian foreign minister: The Holocaust is no myth