Russian “munitions” struck and wounded several fighters belonging to the Syrian Democratic Forces (SDF) near the city of Deir Ezzor earlier today, according to Combined Joint Task Force – Operation Inherent Resolve (CJTF-OIR).

The US military says the location was “known to the Russians to contain” both SDF members and “Coalition advisors.” None of the Coalition troops were injured, but the SDF fighters needed medical treatment. Army Colonel Ryan Dillon, the OIR spokesman, tweeted an image of the wounded, claiming that “[m]any” of the SDF’s members are “from tribes local to” Deir Ezzor province.

“Coalition officials are available and the de-confliction line with Russia is open 24 hours per day,” Coalition commander Lt. Gen. Paul E. Funk II said. “We put our full efforts into preventing unnecessary escalation among forces that share ISIS as our common enemy.”

CJTF-OIR’s statement contained a warning. “The Coalition and its partners remain committed to the defeat of ISIS and continued de-confliction with Russian officials.” However, the statement continued: “Coalition forces and partners always retain the right of self-defense.”

The Assad regime, backed by Iran and Russia, launched an offensive against the Islamic State in Deir Ezzor province this past summer. Earlier this month, the Syrian regime said that its forces and allies had broken through the Islamic State’s siege of its positions in and around Deir Ezzor city. Abu Bakr al Baghdadi’s men began the siege in 2014 and the two sides have frequently clashed in the area since then.

On Sept. 9, the US-led coalition announced that the Syrian Arab Coalition (SAC), which is part of the SDF, had begun its own push into Deir Ezzor province. The new offensive, named “Operation Jazeera Storm,” is focused on the Islamic State’s positions in the Kahbur River valley. The US and its allies aim to dislodge the so-called caliphate from its strongholds north of the city of Deir Ezzor.

With competing coalitions fighting to take ground from the Islamic State in eastern Syria, it was only a matter of time until they clashed. And the US military squarely lays the blame on Russia for the altercation.

The incident earlier today comes just weeks after the Assad regime and Hezbollah, which is also fighting in eastern Syria, cut a controversial deal with the so-called caliphate. The agreement was intended to allow Islamic State jihadists, along with their family members, to travel from Lebanon, where they had been fighting with Hezbollah, to eastern Syria and eventually Iraq. The 11-bus convoy stalled en route after the US objected to the deal. The Russians requested that the US end its surveillance of the vehicles and this eventually allowed them to pass.

After the US ended its surveillance, the convoy first arrived in Mayadin, where the US-led coalition has carried out a targeted air campaign against senior Islamic State personnel. [See FDD’s Long War Journal report, US says 2 more senior Islamic State leaders killed near Mayadin, Syria.] The buses reportedly made their way into western Iraq, despite US objections.

Both the controversy over the bus convoy and the incident east of the Euphrates River near Deir Ezzor earlier today demonstrate that despite “de-confliction,” the US and Russia are often not on the same page in Syria.

Thomas Joscelyn is a Senior Fellow at the Foundation for Defense of Democracies and the Senior Editor for FDD's Long War Journal.

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