Iraqi forces have launched an offensive to retake the city of Mosul, which has been the de facto capital of the Islamic State militant group since 2014. Prime Minister Haider al-Abadi said it would be the toughest battle for the Iraqi military since American troops left nearly five years ago.

Abadi pledged to rebuild Mosul and neighbouring towns and villages and vowed to restore stability to the devastated city. The UN says up to 1.5 million civilians remain in the city, raising concerns that the vastly outnumbered militants could use them as human shields.