The West is floundering over how to respond to Syria’s worsening civil war, especially after a leading Islamist rebel group pledged allegiance to Al-Qaeda, opposition officials and experts say.

The move by the Al-Nusra Front this week has complicated efforts by US and European officials to come up with unified strategy to support the rebels battling the regime of President Bashar al-Assad.

After pushing for weeks to lift a European embargo so arms could be supplied to the rebels, France and Britain have recently backed away from the initiative amid fears weapons could fall into the wrong hands.

Meeting in London this week, G8 foreign ministers said they were “appalled” by the spiralling violence in Syria but made no mention of supplying arms to the rebels.

The rebels’ diplomatic representative in Paris, Monzer Makhous, said he was increasingly sceptical of the West backing up its promises of support for Syria’s opposition with real action.