US troops based in Syria’s southeastern desert have expanded their footprint, rebels there said, increasing the risk of direct ground confrontation between US and Iran-backed pro-government forces.
US special forces have been based since last year at al-Tanf, a strategic Syrian highway border crossing with Iraq, where they have assisted rebels trying to recapture territory from fleeing Islamic State fighters.
The US-backed Syrian rebels in the area are in competition with pro-government forces, who are also trying to recapture territory from the Islamic State.
On several occasions in recent weeks, US-led coalition warplanes have struck pro-government forces to prevent them from advancing, in what Washington has described as self-defense.
Abu al-Atheer, military spokesman for the US-backed Maghawir al-Thawra rebel group, told reporters that US forces had spread from their initial location at al-Tanf to set up a second base at Zakf, about 60km to 70km to the northeast.
Regional intelligence sources told reporters that the US military moved a new long-range rocket launcher system from Jordan to Tanf in the past few days.
They said the High Mobility Artillery Rocket System, which can fire missiles as far as 300km, had been deployed for the first time in southern Syria.
They had been previously used to strike militants from positions in Turkey and Jordan.
Colonel Ryan Dillon, spokesman for the US-led coalition fighting against the Islamic State group in Iraq and Syria, denied troops had set up a new base.
However, he said that sometimes coalition forces conduct patrols and training with rebels at locations outside Tanf that could be maintained for days or weeks.
“We have that garrison in al-Tanf that is a temporary base and location for us to train our partner forces to fight to defeat ISIS, but that is the only base in southern Syria or location where we have coalition forces,” Dillon said, referring to the Islamic State by one of many acronyms used to identify the group.
Abu al-Atheer said the US forces were patrolling distances of up to 100km from al-Tanf.
He said more US special forces were arriving at both the original base at al-Tanf and the new base at Zakf, and more weapons had been delivered to rebels.
“The [new] base was being studied for months, but now it’s an official base. It has been built and expanded and God willing will be in the next few days like the al-Tanf base,” he told reporters.
Video clips purportedly of the Zakf site, sent to reporters by another rebel in the group, showed a convoy of military vehicles traveling on a paved road lined by long walls, a communications mast and a hut.
Another showed three men in uniform next to two small military vehicles, firing a mortar in otherwise empty desert.
US-backed rebels are fighting to oust Islamic State fighters from their last two major bastions — Mosul in Iraq and the Euphrates River valley near Raqqa in Syria — in battles that Washington hopes could crush the group this year.
The Syrian government, backed by Russia and Iran, also wants to reclaim the territory in Syria. Pro-government forces have taken up positions north of al-Tanf, potentially cutting off the US-backed rebels from advancing.