US-backed Iraqi forces have started a ground offensive to dislodge Islamic State militants.
They're trying to weed them out from their remaining stronghold in the western part of Mosul.
Commanders are expecting the battle to be more difficult than it was in the east of the city.
That's because tanks and armoured vehicles can't pass through narrow alleyways in the old parts of the city.
Reuters Iraq correspondent Stephen Kalin told Mike Hosking hundreds of thousands of civilians are also there.
LISTEN ABOVE AS STEPHEN KALIN SPEAKS WITH MIKE HOSKING
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