Iraqi forces continue their fight against Isis on the edge of the Old City in Mosul. The neighbourhood around the al-Nuri mosque is the focus of the advance. Three years ago, Isis leader Abu Bakr al-Baghdadi proclaimed a caliphate there.Narrow streets in this densely populated area have slowed down the army’s advance. Residents say Isis militants use them as human shields. According to the UN, several hundred civilians have been killed in the past month.