Iraqi forces have launched a new push in their battle to capture western Mosul from so-called Islamic State.
Several neighbourhoods have been captured since the US-backed operation began on 19 February, but bad weather has slowed the advance in recent days.
But more than 45,000 people have been forced to flee the city in the last two weeks, the International Organisation for Migration says.
Eastern Mosul was recaptured in January after several months of fighting.
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IS overran the city, Iraq's second largest, as they spread across large parts of the north and west of the country in a major offensive in 2014.
Joint operations command (JOC) spokesman Brig-Gen Yahya Rasool told state TV on Sunday that Iraqi forces were advancing towards the old centre of the city from the south and south-west.
JOC statements quoted by AFP news agency said security forces were attacking the neighbourhoods of al-Dindan, al-Sumood, Tal al-Raman and al-Dawasa, where the provincial governor's offices are located.
The IOM, the UN migration agency, says more than 200,000 people have been displaced by the fighting since October last year, with a new exodus beginning on 25 February.
Up to 700,000 people are believed to remain in the city.
Centres for the displaced have been filling up quickly, with 7,619 families (45,714 individuals) arriving in the last nine days, it said.