Iran is a longtime ally of Syria's President Bashar al-Assad and, alongside Russia, helped stave off his overthrow at the hands of Sunni rebels backed by Turkey. Little is known about Iran's presence in Syria however. Western journalists do not have access to their zones of influence. Yet there is persistent talk of the establishment by Iran of a Shiite Crescent stretching from its borders through Iraq and Syria on to Lebanon. Israel and the United States have escalated attacks against Iran backed militias in Syria in recent days. Meanwhile Iranian Turkish tensions in Syria are brewing anew. Iranian expert Hamidreza Azizi says while the two share animosity against the Kurds, Iran has formed a tactical alliance with some Kurdish groups against Turkey. In the meantime, he warns failure to reach a new nuclear deal could see Iran taking action against Israel in Syria and beyond.