President Assad has bussed 400 Isis fighters into Syria’s last rebel-held province, according to observers, complicating the stand-off over Idlib’s future.

The fighters had been surrounded by regime troops in the far east of the country, in the province of Deir Ezzor on the Iraqi border.

The Syrian Observatory for Human Rights says that a surrender deal has been negotiated along the lines of many previous such arrangements by both the regime and the Kurdish-led forces fighting Isis, under which the fighters have been transported elsewhere. In this case, the regime has done the same as it has with thousands of other rebel or jihadist fighters: bus them to Idlib, the last remaining significant rebel hold-out. They arrived on Monday morning, according to one report,