For years, Arab and western officials have kept a watchful eye over an arid tract of land in a remote corner of the Middle East, where US troops, Iran-linked militias and the remnants of Isis all operate.
Tehran-backed militants sit at checkpoints and makeshift bases along the Baghdad-Damascus highway, which they long ago seized — the centre of a highly prized smuggling network in the border triangle, used by militants and criminal gangs to smuggle drugs and weapons.
On Sunday, this corner between Jordan, Syria and Iraq became the latest flashpoint in the widening regional hostilities that have drawn the US back into combat.
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