The representative of Iraq's most senior Shia cleric has said religious leaders, "started to sense a real danger which threatens Iraq", following the fall of Mosul and Tikrit to ISIS.

Grand Ayatollah Ali al-Sistani's representative Sheikh Abdul Mahdi Karbalai was speaking exclusively to BBC World Affairs Editor John Simpson.

He said the threat from ISIS was to "Iraqi people and Muslim holy shrines - from all sects".