In fight for Aleppo, tangled alliances add to chaos

The Syrian civil war, and the intense new ground battle in the divided city of Aleppo, is often seen as a contest between a chaotic array of rebel groups and the Russian-backed government of President Bashar Assad. But the reality is that Mr Assad's side is increasingly as fragmented as its opponents, a panoply of forces aligned partly along sectarian lines but with often-competing interests.