Reports in the Arab and Iranian press suggest that Russian forces are amassing near a town along the Euphrates River in Der Ez Zor province, Syria. While those reports are hard to corroborate, there's good reason to believe them.

After all, the town in question, Al Mayadin sits on the Euphrates demarcation line that separates Russia and its Syrian and Iranian allies from U.S. forces in northern and eastern Syria. And as the map below shows, with Al Mayadin (blue square) located along a key highway from Iraq (green circle) which connects with two other highways; one running north across the Euphrates and one running east towards southern Syria. That gives Al Mayadin key strategic value as an artery for Iran's land supply network to its forces and allies in Syria and Lebanon





So what are the Russians up to here?

Two things, I think. First off, the Russians want to ensure they are the ones who decide what interests pass through Al Mayadin. With Russian objectives in Syria increasingly separated from those of Iran, controlling Al Mayadin affords the Russians more leverage in their dealings with Israel. That's because Vladimir Putin wants to convince Israeli Prime Minister Benjamin Netanyahu that he will support constraint of Iranian weapons smuggling through areas like Al Mayadin if the Israelis are willing to pressure the U.S. to accept Bashar Assad's retained rule over Syria.

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At the same time, however, Russian re-positioning alongside the Euphrates allows Putin to threaten American forces east and north of the river. Russia is deeply agitated by President Trump's decision ( to his credit) to keep U.S. forces in Syria in that the U.S. presence gives America influence over Syria's political process. Those forces also give the U.S. means to pressure Assad against wholesale slaughter of civilians in places like Idlib.

Yet the key point here is that the Russians have repeatedly sought to push U.S. forces out of Syria by launching thinly veiled attacks against them. Fortunately, Defense Secretary Jim Mattis has given the U.S. military the authority it needs to defend itself. He will do so again if the Russians decide to be stupid again.

Ultimately, though, we should pay close heed here. Russian ground force movements in Syria are always worth watching.