“But Anthony Cordesman, a military expert at the Washington DC-based Centre for Strategic and International Studies, cautioned against reading a nationwide strategy into the local tactics of disparate rebel cells.

“We don’t know frankly whether Aleppo is a strategy from one major faction of the insurgents, whether its a reaction to success in Damascus, whether it simply represents an obvious target that hasn’t been attacked because the insurgents felt they were too weak or not properly supplied and equipped.”