Iraqis 'make gains against IS in Tikrit battle'

Iraqi government forces say they have retaken some districts around Tikrit in their fight to recapture the city from Islamic State militants.

A force of about 30,000 troops and militia are said to be attacking on different fronts, backed by air strikes from Iraqi jets.

A commander of Iran's Revolutionary Guards is taking part in the operation, a Shia militia commander told the BBC.

James Robbins reports.