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Copyright © 2019 The American Israel Public Affairs Committee

Analysis: Iran Hopes to Fill Post-ISIS Vacuum in Eastern Syria

The limited ceasefire in southwestern Syria, which went into effect last month, ostensibly uses Russian police forces to prevent Shia militias—including Lebanese Hezbollah—involved in the Syrian civil war and led by Iran’s Islamic Revolutionary Guard Corps from establishing themselves on the borders of Israel and Jordan.

Tehran and Damascus accepted and began implementing this ceasefire with their Russian allies because they apparently believe it will prove to be a boon for their long-term aspirations in Syria. Quiet in the southwest allows them to concentrate their limited military resources in eastern Syria, where they are winning the battle against the Islamic State (ISIS) and laying the groundwork for an Iranian-controlled land-bridge stretching from Iran to Lebanon. Once they have achieved victory in the east, Iran, Hezbollah and Syria may decide to move their forces toward the Israeli and Jordanian borders. There is no assurance that Moscow will use its police units deployed to enforce the ceasefire to thwart this potential advance.

Iran is bidding for regional dominance.

Since the 1979 founding of the Islamic Republic, Iran has sought to “export” its revolutionary presence throughout the Middle East in a bid to restore Persia’s traditional role in the region and supplant American influence. Tehran—flush with cash from sanctions relief under the 2015 nuclear deal—and its loyal terrorist proxies are working to destabilize the Middle East, inflame sectarian tensions, and support Assad’s bloody war in Syria. Iran has also intervened in Iraq—where it controls Shia militias larger than the Iraqi Army—Bahrain and Yemen. The overarching goal of these interventions is to establish Iranian political and military regional primacy, position Tehran to lead the radical Muslim struggle against Israel, and export the Islamic Revolution to Shia communities throughout the Middle East.

Syria is vital to Iran because it provides a critical piece in the “land bridge” stretching from Tehran to Beirut via Mosul in Iraq and the Syrian cities of Deir ez-Zour and Damascus. Hezbollah and other Iranian-led fighters are currently pushing east from Aleppo towards Raqqa to conquer Deir ez-Zour—the key to controlling eastern Syria and completing the strategic “land bridge.” Such a route would enable the land transport of large numbers of weapons and fighters from Iran to Syria and Lebanon. This accomplishment would greatly benefit Tehran, especially if it were to lose access to the Beirut and Damascus airports during a future Hezbollah conflict with Israel. If Iran and Assad achieve control over eastern Syria at the expense of ISIS, they will almost certainly turn their attention to reconquering the two remaining pockets of anti-Assad Arab rebels located in the northern province of Idlib, by the Turkish border, and in the southwest, including the Syrian Golan Heights.

Israel is alarmed by Tehran’s ambitions.    


Israel is wary of Iran establishing itself and its Shia proxy militias next to the Israeli Golan Heights border with Syria, and worries that the flow of Iranian arms to Hezbollah will increase. Israel suspects that Hezbollah—emboldened by Tehran’s success in Syria—will eventually seek open conflict with the Jewish state. Hezbollah has invested extensive resources and taken many casualties in Syria, but it has also gained invaluable battlefield experience that will make it a much more formidable foe if it resumes hostilities against Israel.

Israel is unlikely to countenance Iranian troops or proxies approaching Israel’s borders. In response to the latest ceasefire, the Israeli security cabinet convened to discuss its concerns and to endorse the three Israeli “red lines” in Syria, previously laid out by Prime Minister Benjamin Netanyahu. Israel will oppose:

  • An established presence of Iran and Hezbollah-led Shia militias on Israel’s northern border.

  • The permanent “establishment of an Iranian military presence in Syria as a whole.”

  • Hezbollah’s acquisition of “precision weapons.”

What next?

Securing a corridor of unbroken Iranian and Iranian-backed Shia influence from Tehran to Beirut would be a major victory in Iran’s project of regional Middle East hegemony. Stemming the Iranian tide will become increasingly difficult for Tehran’s opponents as Iran, Russia and Assad get closer to wiping out the vestiges of ISIS’s “Caliphate” in eastern Syria.

On Aug. 1, U.S. Secretary of State Rex Tillerson stated, “The direct presence of Iranian military forces inside of Syria, they must leave and go home, whether those are Iranian Revolutionary Guard forces or whether those are paid militias—foreign fighters—that Iran has brought into Syria in this battle.”

Israel may eventually go beyond its current efforts to interdict Iranian arms shipment and take far more extensive action to defend itself. Israeli Defense Minister Avigdor Lieberman had a clear message to Iran last month: “We [Israel] retain exclusive responsibility for the security of Israeli citizens, and therefore our freedom of action is absolute. We will do everything that is needed.”