A delicate security triangle is forming along the Syrian-Iraqi borders. Operational lines of separation have prevented the United States, Iraq and the Damascus camp from working together to fight ISIS. But new complications have forced a fresh dynamic that effectively enables the US to target ISIS outside its established jurisdiction by proxy, through the Iraqis.
The new dynamic, while still nascent, is a product of improvised arrangements between Washington and Moscow to prevent aerial collision and to demarcate areas of operation during the fight against the extremist group. The two sides agreed to have the Euphrates river as the "deconfliction" line, despite obvious flaws more apparent now than a few months ago.
ISIS has already started to exploit these flaws and gaps, forcing presumed rivals to engage in backdoor measures to address emerging problems.
This turn of events began in March after Kurdish fighters in Syria shifted their focus to the Turkish operation in Afrin away from the war against ISIS and while the Syrian regime started to focus on rebel strongholds near Damascus. The US-led coalition then announced an "operational pause" in the remaining villages still under ISIS control east of the Euphrates. The villages, around five in total, are part of the administrative region of Abu Kamal near the Syrian-Iraqi borders, where the regime controls the other side of the river.
In a conversation in mid-March, American officials told me of an awkward situation along the western side of the river, specifically in the villages situated between the regime-held city of Abu Kamal and the Iraqi city of Al Qaim. The Syrian regime claimed to have liberated those small villages in November with the help of Iranian-backed militias. But according to American officials, that was not the case.
Since the US was not allowed to strike against ISIS in supposedly regime-held areas, the situation allowed the militants to operate with impunity in that area. ISIS fighters moved freely along and across the river. Similarly, the operational pause allowed ISIS in the non-liberated villages east of the river to refocus its attacks on the regime side. According to residents from Deir Ezzor at the time, ISIS fighters would cross the river and connect with other members operating in the Syrian Desert west of Abu Kamal, a possible factor in recent successful attacks by ISIS, deep in regime areas near Palmyra.
Not long after the US officials expressed their growing concerns about ISIS's presence near the borders, Baghdad announced it would conduct attacks against the group inside Syria. “The real danger is the presence of ISIS in Syria,” Haider Al Abadi, the Iraqi Prime Minister, said in a press conference this month. “We heard that they got rid of ISIS. Lies.”
The statement was in response to US concerns about ISIS activities outside its operational purview. Iraq was able to use its friendly ties with the Syrian regime and Iran to target ISIS in regime-held areas.
"The majority of the support that the coalition provided was intelligence support on the target," colonel Ryan Dillon, the anti-ISIS coalition's spokesman, said, referring to an Iraqi strike against ISIS headquarters inside Syria. "We also provided some other assets in the air nearby that were also a part of the support package. But it really was the Iraqis who planned this all the way through. It was their commitment and their coordination with their neighbours in the Syrian government, before they conducted these strikes."
Mr Al Abadi referred to these pockets, in which ISIS still operates despite regime claims, as “deserted” by Syria. For this reason, he said, his government found it vital to take the fight against ISIS to Syria. He said while his armed forces control all the borderline from the Iraqi side, ISIS individuals still manage to cross it to conduct attacks inside the country either through border gaps or bribery.
Such de facto three-way operations are poised to continue, if not intensify. As I wrote last week, ISIS is pushing its sleeper cells to become active again. The push appears to be part of a broader effort to rekindle its insurgency after the loss of territory and comes at the backdrop of increased attacks in much of Iraq and Syria. The effort to reignite the insurgency culminated with a fiery speech on Sunday by the group's spokesman, Abu Al Hassan Al Muhajir, the first by one of its senior leaders since September, urging members to intensify their campaign.
Using the river as a deconfliction line is likely to remain a nuisance for the US, Iraq and the pro-Syrian camp. ISIS has a history of using rivers and areas adjacent to them as hideouts and for mobility, even when the US was heavily present inside Iraq after 2007. The villages that the US complained about in regime areas contain, more than the rest of Abu Kamal, lush river reeds and palm orchards that make it easier for militants to hide and survive.
Another factor that might complicate the situation for ISIS enemies is that in Abu Kamal specifically, the river passes through the Syrian-Iraqi borders. At that confluence point, three items favourable to ISIS converge: the river, the Syrian and Anbar deserts and the borders.
Ideally, this area should have been controlled by a force or a group of forces that closely work with each other, as one senior US official conceded. Instead, different countries that supposedly operate under different jurisdictions control different parts of a critical terrain. In this context, ISIS will no doubt find gaps, as it already has, that cannot be plugged by tactical strikes on occasions.
A few months ago, such a complexity was not anticipated. Each side was racing to carve out areas of control as they battled ISIS. They rushed to agree on demarcated lines to avoid accidents. But the latest developments only demonstrate, once again, that the US-led coalition is still improvising as it goes – hardly a reassuring sign for a lasting defeat of ISIS.
Hassan Hassan is co-author of the New York Times bestseller ISIS: Inside the Army of Terror and a senior fellow at the Tahrir Institute for Middle East Policy, Washington DC