Insurgents capture army air base in northwestern Syria

The loss of Abu Duhur is the latest setback for Mr Assad’s forces, which the president acknowledged in July were suffering from “fatigue”.

President Assad has admitted that his forces have a manpower problem and would have to give up some areas in order to defend more important ones.

The airport, which was one of the last remaining military strongholds in Idlib province, has been under siege for nearly two years by rebels.

This makes Idlib the second of Syria’s 14 provinces to utterly fall out of Syrian military management. The extremist group’s strength, paralleled with the rise of the Islamic State, also known as ISIS, has led to the weakening of moderate opposition groups supported by the US and other Western countries.

Insurgents now control almost all of the province, except for the predominantly Shia villages of Foua and Kfarya which are held by pro-government militias and Lebanese Hezbollah forces, not the Syrian army.

Dozens of others were either taken prisoner or went missing when the Al-Nusra Front and a coalition of mostly Islamist groups captured the Abu Duhur military airport yesterday, the Syrian Observatory for Human Rights said.

In the latest issue of its English-language magazine Dabiq, IS published the boy’s image under the headline: “The danger of Abandoning Darul-Islam”, or the land of Islam, including the group’s self-declared caliphate in Syria and Iraq.

Syrian state TV quoted an unnamed military official as saying that troops pulled out of the Idlib base with weapons, and that none of the equipment and warplanes left behind “were usable”. Rebels drove out government forces from the provincial capital in March – considered a major win for al Qaeda in Syria. The source added that not all government forces had withdrawn and clashes were continuing.

On its website, the group said that the rebels had “taken advantage of bad weather and sandstorms” to launch the attack. Refugees at the moment are streaming into Europe in an unprecedented on the continent.