>> The campaign to retake Mosul from Islamic State well underway. Iraqi and Peshmerga forces advancing to oust militants from their Iraqi strongholds. But what's their plan of action? And how long will it take? Reuters Dominic Evans explains how the offensive is likely to play out.>> There's a range of forces, mainly built up to the south is the Iraqi Army.
They captured a major airbase, the Qayyara Airbase, back in July. That's now become the staging point, if you like, for the campaign now. The Iraqi forces are supported by American troops and advisors. Then more to the north and to the east of Mosul, Peshmerga fighters, the Kurdish fighters, who have been advancing in last 36 hours.
I think the expectation is that Mosul will be retaken. It will take weeks, it may take months. This is the easy stage. The areas that they're taking at the moment, that they're advancing through, are for example, they're very flat plains east of Mosul, the Nineveh plain, most of the villages there have been deserted.
Once they get to the outskirts of Mosul and to the city itself, of course, everything changes. There are more than 1 million civilian residents in Mosul at the moment. Their presence obviously makes the military operation hugely more complicated. It will slow things down and that sheer size of the city means it is unprecedented in terms of operations that have been carried out for the last two years in Iraq.
It is five times bigger than the biggest city that they have so far recaptured from Islamic state. Previous campaigns including Tikrit, Fallujah Ramadi and Baiji, often in both. Many long weeks of besieging the city surrounding them, cutting off all the access routes then bombarding, targeting the main centers of Islamic state strength before ground troops went in.
So it will be fought, it will be difficult as the weeks unfold