Iraqi forces made fresh gains in central Ramadi Sunday and tightened the noose around holdout militants making their last stand in the former government complex, officials said.
The elite counter-terrorism forces and army troops backed by Iraqi and US-led coalition air strikes vastly outnumbered the few holed up fighters from the Islamic State group.
But hundreds of booby traps and roadside bombs combined with sniper fire and suicide car bomb attacks meant that, six days into their big push, Iraqi forces still had some fighting to do to retake the city they lost in May.
"The forces have arrived at the gates of the complex" after recapturing three nearby buildings, said Raja Barakat, a member of the Anbar provincial council.
Ramadi lies about 100 kilometres (60 miles) west of Baghdad and is the capital of Anbar, which is Iraq's largest province and has borders with Syria, Jordan and Saudi Arabia.
A victory in Ramadi would help boost Iraq's much-criticised military, which collapsed when ISIS took over large parts of the country in June 2014.
A senior officer from Iraq's 8th army division said the latest fighting around the government complex left several ISIS militants dead.
"Seven of our forces were also wounded in these clashes and as a result of the explosion of mines," he said.
At least five members of the security forces were killed since Friday, according to several security sources, although the government has not divulged an overall casualty toll for the Ramadi operation.
Estimates at the beginning of the operation were that no more than 400 ISIS fighters remained hunkered down in central Ramadi and dozens have since been killed.
Iraqi military sources have reported that more than 50 militants were killed in the past 48 hours alone.
The first push into central Ramadi on Tuesday was met with limited resistance but ISIS fighters had set up strong defences around the government complex.
They also rigged the entire town -- roads, abandoned positions, houses -- with explosives, which has required a huge mobilisation of ordinance experts and slowed the military advance.
The army officer said 260 improvised explosive devices were defused on Ramadi's northern front this weekend alone.
Another impediment to the Iraqi forces' advance in Ramadi has been the continued presence of pockets of civilians in combat zones, many of them used as human shields by ISIS.
Civilians who escaped said after being taken by the army to camps east of Ramadi that there was little food for those left behind.
One of them said he and his family were rescued after retreating ISIS fighters used them as human shields to leave the city.
"More than 250 families residing in Ramadi have been able to get out of the city since the beginning of military operations" on Tuesday, said Ali Dawood, an official from the neighbouring Khaldiya district.
He said some of them were in camps with other displaced people in Anbar, while others headed to Baghdad or the northern autonomous Kurdish region.
According to the International Organization for Migration, Anbaris account for over a third of the 3.2 million Iraqis who have been forced from their homes since January 2014.
Government forces held off months of ISIS assaults in Ramadi until May 2015, when the militants blitzed their opponents with massive suicide car bombs and seized full control of the city.
The fightback has often been laborious and poisoned by political wrangling, but Defence Minister Khaled al-Obeidi said a week ago that Iraqi forces had reclaimed half of the territory lost to ISIS last year.