Western Special Forces, operating alongside rebels in the New Syria Army, have taken control of the military airport of Hamedan just three miles to the north-west of the Islamic State (Isis) stronghold of al-Bokamal.
The Syrian Observatory for Human rights has said in a statement on 29 June that the strategic military airport near the Iraqi border was taken following fierce clashes between the US-backed forces and the militant group. Three helicopters were used in the attack and no casualties were reported.
Warplanes from the coalition against Isis have continued aerial bombardments in the town, dropping leaflets to civilians trapped inside.
Hours later, IS news propaganda arm the al-Amaq agency released pictures of three civilians in al-Bokamal the militants had executed for supporting the New Syria Army, with a new curfew imposed on the town, according to reports on social media.
The New Syria Army was formed 18 months ago by rebel fighters from eastern Syria, pushed from their territories by the Islamic State as it began it's rapid expansion in 2014 following the capture of Mosul in Iraq.
The continued involvement of special forces in the fight against the Islamic State follows reports in June that British elite troops stationed in Jordan had fought against IS with the New Syria Army in al-Tanf to head-off IS attacks.
It was was the first time evidence has emerged of Britain's direct involvement on the ground in the Syria conflict.
The settlement, strategically positioned at a crossroads in Syria between Iraq and Jordan, was overrun by IS in March. However, New Syrian Army forces, trained and equipped by the US and its allies and part of an ill-fated Pentagon attempt to create a moderate armed Syrian opposition, retook al-Tanf in March.