Iraqi government forces - including troops trained in urban warfare by New Zealand soldiers - are moving closer to the centre of the city of Ramadi, despite fierce battles with Islamic State (IS) militants.
An Iraqi army spokesperson said the troops were being slowed by bombs, snipers and booby traps.
Troops and Sunni tribal fighters were about 500m from the main local government office, and had taken control of several districts since launching the operation five days ago.
The mainly Sunni Arab city, about 90km west of Baghdad, was captured by IS in May.
Its fall was seen as an embarrassing defeat for the army.
Iraqi officials said troops had now managed to enter the area of Haouz - one of the most important IS strongholds in the centre of Ramadi, which includes the main offices of the Anbar province administration and the police directorate.
Joint operations command spokesman Brig Yahya Rasool told Reuters that US-led coalition air strikes "helped detonate explosive devices and booby-trapped houses, facilitating our advance".
Police captain Ahmed al-Dulaimi spoke of "fierce battles" that had killed many IS militants.
Concern for civilians
At the launch of the operation on Tuesday, the Iraqi army said it expected up to 300 militants inside the city centre to be dislodged within days.
But there was concern for civilians reportedly taken prisoner by the militants.
Sources in Ramadi said on Tuesday the jihadists had carried out raids and mass arrests, in an attempt to prevent an uprising in support of the government offensive by the thousands of people living in districts under their control.
The operation to recapture Ramadi, which began in early November, has made slow progress, mainly because the government chose not to use the powerful Shia-dominated paramilitary force that helped it regain the northern city of Tikrit, to avoid increasing sectarian tensions.
IS has lost control of several key towns in Iraq to government and Kurdish forces since over-running large swathes of the country's west and north in June 2014 and proclaiming the creation of a "caliphate" that also extended into neighbouring Syria.
- RNZ / BBC / Reuters