Iraqi forces battled to retake districts of western Mosul still under Islamic State control on Monday, in an attempt to seize victory before the holy month of Ramadan.
After seven months of fighting, militants have been dislodged from all but a few areas of Mosul. Islamic State is expected to make a last stand around the Old City's Grand al-Nuri Mosque, where the Islamist group's black flag has been flying since June 2014.
Backed by U.S.-led coalition air strikes and advisers, Iraqi forces have made rapid gains since opening a new front in the northwest of Mosul earlier this month, closing in on the Old City.
Outnumbered, militants have retaliated with suicide car bombs and snipers embedded among the hundreds of thousands of civilians trapped in west Mosul. Many local people have been killed by militants or heavy bombardments.
"If we advance this quickly we can finish it in days," First Lieutenant Nawfal al-Dhari told Reuters at a house turned into a temporary base in the western Islah al-Ziraie district, retaken by Iraqi forces three days ago.
"These are their dying breaths. They are completely surrounded."
He said the momentum was with Iraq's elite Counter Terrorism Service (CTS), the U.S.-trained special forces who have led the campaign to retake the country's second city, despite continued resistance from Islamic State fighters.
"If you trap a cat in a room, it will scratch," he said.
Retaking the mosque, where Islamic State leader Abu Bakr al-Baghdadi in 2014 declared a "caliphate" spanning swathes of Syria and Iraq, would be both a symbolic and strategic victory.
Military commanders and intelligence officials say they aim to take control of al-Nuri mosque before Ramadan starts at the end of this month so they can declare the battle won, even if the militants continue to hold out in pockets.
They said the number of Islamic State militants still fighting was shrinking, and they were increasingly disorganized and short of arms, ammunition and equipment following months of siege.
"Daesh are losing the ability to fight back. It's obvious they are blundering. We want to make the Old City a closed death casket for Daesh," an Iraqi army intelligence colonel said, using an Arabic term for Islamic State.
"Yes there will be remnants of Daesh inside the Old City, but it will be as easy as hunting rabbits to take them down."
The warren of densely packed houses and alleys, with Roman, Ottoman and Persian traces, has proved a complex battleground for Iraqi troops against a skilled enemy willing to use civilians as shields.
Iraqi forces have tried to open up several fronts in an attempt to split Islamic State militants, who have had two years to prepare their defenses.
U.S.-backed air strikes in the tightly-packed neighborhoods have been made more difficult, government forces say, by their efforts to avoid civilian casualties.
The Iraqi government said last week the number of people fleeing Mosul had more than doubled to about 10,000 a day.
"Our advance on a vast front has stunned the enemy and, God willing, we will achieve victory before Ramadan and announce the liberation of Mosul and people of Mosul from the dirtiness of Daesh," Lieutenant General Othman al-Ghanmi, chief of staff, said in a video distributed by the Defence Ministry.
He was speaking on a visit to the front lines in western Mosul. Ramadan is expected to start on May 27.
"The more they are besieged the harder they fight. They have nowhere to go," soldier Faris Sallal said in the Islah al-Ziraie district, which echoed with intermittent gunfire and the occasional boom of artillery.
Flies swarmed over the charred remains of an Islamic State militant lying near a motorbike. In the garage of a house on the same street was an armor-plated car rigged with a suicide bomb.
In the nearby Ureibi district, partly controlled by Iraqi forces, a Reuters reporter saw the bloodied corpse of an Islamic State sniper in a children's room on the upper floor of a house.
Iraqi forces, now using the house as an outpost, said the sniper had been targeting advancing Iraqi troops.
Colonel Mohammed al-Taie of the Operation Command in the surrounding Nineveh province said Iraqi forces were advancing rapidly north of Mosul.
"Our intelligence conclusions based on insider sources and drone surveillance indicate undisputedly that Daesh fighters are less organized now and lack the resources to keep fighting," he said.