The US-led coalition in Syria responded to an attack by Syrian pro-regime forces on Wednesday, according to a statement from the Combined Joint Task Force, Operation Inherent Resolve. More than 100 fighters from the pro-regime side were killed in an unprecedented and large clash that included tanks, artillery and rockets.“Syrian pro-regime forces initiated an unprovoked attack against well-established Syrian Democratic Forces headquarters,” the initial coalition statement said.The SDF is the umbrella group of partner forces that the US works with in eastern Syria.The attack began late in the evening on Wednesday and lasted until the early morning Thursday. “Pro-regime forces initiated hostilities with artillery pieces (D-30/M-30 type).Additionally, Syrian pro-regime forces maneuvered T-55 and T-72 main battle tanks with supporting mortar fire in what appears to be a coordinated attack on Syrian Democratic Forces approximately 8 kilometers east of the Euphrates River deconfliction line in Khusham, Syria,” Col. Thomas F. Veale, coalition public affairs officer, wrote in a statement.The coalition had been observing a buildup of the forces over the past week and alerted Russian officials to the SDF presence. “Russian officials assured coalition officials they would not engage coalition forces in the vicinity,” the statement said.According to the coalition, a headquarters of the Syrian Democratic Forces came under fire from artillery and tanks. Around 20 to 30 shells hit within 500 meters of the headquarters. “Coalition advisers were with the SDF in advise, assist, and accompany- capacity, and this action was taken in self-defense,” it said. The “agreed-upon Euphrates River deconfliction line” is a line the coalition and the Syrian regime have agreed to that their forces are not supposed to cross, in order to prevent conflicts. With the defeat of Islamic State in most of Syria, the coalition and the Syrian regime share a long “deconfliction” line mostly along the Euphrates River.
The coalition used artillery and air strikes to break the enemy’s line of advance. After the attack, the coalition “conducted strikes against attacking forces to repel the act of aggression.” But they stressed it was all in self-defense and that pro-regime vehicles which turned around were not targeted.A coalition official told Reuters that the attacking forces were “likely seeking to seize oil fields in Khsham that had been a major source of revenue for Daesh [ISIS] from 2014-2017.”According to Liveuamap, a site that maps the conflict in Syria, the town of Khusham near Deir al-Zor is actually held by the Assad regime, while the nearby Conoco-Tabiya gas plant is several kilometers from the line that separates the SDF from the regime.That would indicate that the attack came from the area of Khusham. In September 2017, the SDF liberated the gas fields. Since then, there have been rumors that the regime and its Russian backers would like to find a way to return the fields to the hands of Damascus. Before Turkey’s Afrin operation in January, Kurdish sources said they had been pressured to hand over the gas field in exchange for the regime preventing a Turkish offensive against the People’s Protection Units (YPG) in Afrin. The YPG is one of many groups that makes up the SDF.The coalition has stressed in statements and tweets that it “communicated through deconfliction line with Russians before, during and after attack.”CNN has postulated – based on a US official’s comments – that the US was “looking into whether Russian contractors operating in the vicinity might have been involved.”In addition, they said the US has “not ruled out that Iranian- backed forces might have been involved in the attack.”In October two Russian contractors were murdered by ISIS. There are thought to be hundreds of Russian contractors serving with pro-regime forces.The attack on the SDF by pro-regime forces marks an unprecedented escalation in eastern Syria between the regime and the coalition. The coalition has warned over the past year against any attacks on its SDF partners. In June 2017, the US shot down a Syrian jet after clashes near Tabqah. The coalition says this time it was defending its partner forces, but the alleged death toll among the pro-regime forces will certainly send a message that Washington is serious about sticking with its partners.In October two Russian contractors were murdered by ISIS. There are thought to be hundreds of Russian contractors serving with pro-regime forces.The attack on the SDF by pro-regime forces marks an unprecedented escalation in eastern Syria between the regime and the coalition. The coalition has warned over the past year against any attacks on its SDF partners. In June 2017, the US shot down a Syrian jet after clashes near Tabqah. The coalition says this time it was defending its partner forces, but the alleged death toll among the pro-regime forces will certainly send a message that Washington is serious about sticking with its partners.