MOSUL, Iraq - US-backed Iraqi forces pushed deeper into western Mosul on Saturday after retaking the city's airport from Islamic State and punching into built-up areas of the jihadists' last major stronghold in the country.
Troops advanced in several more populated, built-up southern districts and about 1,000 civilians walked across the frontlines, the largest displacement since fighting began a week ago in a bid to deal Islamic State a decisive blow.
The new offensive comes after government forces and their allies finished clearing Islamic State from eastern Mosul last month, confining the insurgents to the western sector of the city bisected by the Tigris river.
Commanders expect the battle in western Mosul to be more difficult, in part because tanks and armored vehicles cannot pass through the narrow alleyways that crisscross ancient districts of the city.
But Iraqi forces have so far made quick advances on multiple fronts, capturing the northern city's airport on Thursday, which they plan to use as a support zone, and breaching a three-meter high berm and trench set up by Islamic State.
The advancing forces are now less than three kilometers (two miles) from the mosque in Mosul's old city where Islamic State leader Abu Bakr al-Baghdadi declared a caliphate in 2014 spanning Iraq and Syria, sparking an international military campaign to defeat the group.