Iraqi forces begin operation to retake town from Islamic State

US-backed Iraqi forces have launched a multi-pronged assault to retake the town of Tal Afar, west of Mosul, marking the next phase in the country's war against Islamic State.

Tal Afar and the surrounding area is one of the last pockets of IS-held territory in Iraq after victory was declared in July in Mosul, the country's second-largest city.