SYRIAN insurgents attacked army positions in the southern desert on Tuesday night as relations with their US backers fractured.

The Ahmad al-Abdu and Osoud al-Sharqia factions of the Free Syrian Army (FSA) claimed that they had seized Bir Mahroutha and Umm Rumam.

The villages lie in the southern Badia or desert region to the west of al-Tanf on the Iraqi border, where occupying US and British special forces have set up shop and declared a 35-mile exclusion zone to Syrian troops.

On Monday another faction of the FSA, the Shohadaa alQraiteen Brigade said that US forces had threatened to bomb its positions and headquarters near al-Tanf if they refused to return arms and vehicles provided by the US-led “coalition.”

Spokesman Abu Omar alHomsi said the demand came after the brigade attacked Syrian troops and their Lebanese Hezbollah allies on July 17 and took control of alGhorab and al-Halba mountains.

He said the jihadists would not return “Toyota cars, medium weapons, light weapons and a number of lorry vehicles to the international coalition and will continue to use them against the Syrian regime.”

On Tuesday a group of Maghaweer al-Thawra guerillas went over to the government side, the second defection from the US-backed group in the southern Badia area in a week.

US Secretary of State Rex Tillerson said on Tuesday that the US wanted a stable and “unified” Syria after the defeat of Isis.

But he demanded Iranian troops, supporting the government, leave the country and insisted: “The Assad regime has no role in the future governing of Syria.”