Syrian opposition fighters said they have captured an airport near the Iraq border used by President Bashar al-Assad's forces, Reuters reported.
The BBC confirmed the airport of Hamdan in Deir al-Zour province had been used by Syrian government forces for military purposes.
Located near Albu Kamal, the rebel advance helps strength their hold on the town.
Reuters said video published by the rebels, but unconfirmed by GlobalPost, showed fighters at an air base in Deir al-Zor province.
The Syrian Observatory of Human Rights said rebels now controlled "large swathes of land in the area," the BBC reported.
Reuters quoted activist Ziad al-Amir as saying Assad's forces have retaliated by bombing the airport.
Meanwhile, France said Syria's newly-formed umbrella opposition group would appoint an ambassador to Paris.