MOSUL, Iraq -- Iraqi forces are steadily closing in on the remaining pockets of territory held by the Islamic State group in Mosul, inching toward a victory that U.S.-led coalition officials say is "only a matter of time."
But unlike past urban battles against IS in Iraq, the militants in Mosul are under siege by Iraqi forces.
The Iraqi government on Friday announced a call for all civilians in the Old City to flee, but human rights groups warned the orders could force tens of thousands into deadly front-line clashes.
The decision to surround the remaining IS holdouts is prolonging an already grueling fight, according to Iraqi commanders, and is punishing civilians being held by IS as human shields.
In the fight for Fallujah and Ramadi, cities that were also overrun by IS in 2014 as the group seized vast swaths of territory in Iraq, there was a tipping point in the battles -- the moment when the militants' hold on a city had shrunk to only a handful of neighborhoods. At that point, senior IS fighters began to flee in greater numbers, the extremists' command and control dissolved, defenses crumbled and Iraqi ground forces racked up a series of swift gains.
But in Mosul, Iraq's second-largest city after Baghdad, Iraqi forces backed by the U.S.-led coalition have shrunk IS-held territory to less than 5 percent of the city and still resistance has remained stiff.
In what was meant to be a simple clearing operation last week, Iraqi Maj. Ihab Jalil al-Aboudi and his unit were pinned down for hours at a residential intersection in western Mosul just a few hundred meters from the Old City.
By afternoon, at least three coalition airstrikes were called in to clear IS fighters armed with medium machine guns and rocket-propelled grenade launchers.
"Because the enemy cannot flee, the area is completely sealed off," said Brig. Gen. Haider Fadhil of Iraqi special forces. He said it's impossible to predict how the next few weeks of the Mosul operation will play out, but so far the siege of the Old City is slowing progress on the ground.
"We are noticing that the closer we get to the Old City, the greater the resistance," he added, looking over the roughly 8 square kilometers (3 square miles) of Mosul territory still in IS hands on a satellite mapping app.
The Old City -- a warren of tightly packed homes and roads that shrink to the width of footpaths -- holds special significance for Mosul's residents and IS. The district is home to much of Mosul's ancient heritage, including the Iconic leaning minaret of the al-Nuri Mosque where IS leader Abu Bakr al-Baghdadi declared an Islamic caliphate stretching across IS-held lands in Syria and Iraq in June 2014.
U.S. defense officials say "taking the time" to surround Islamic State strongholds is part of a new approach in the war against IS under the Trump administration, aimed at preventing militants from regrouping after territorial losses and foreign fighters from fleeing.
"The foreign fighters are the strategic threat, should they return home," Defense Secretary Jim Mattis said at a Pentagon briefing on May 19. "So by taking the time to de-conflict, to surround and then attack, we carry out the annihilation campaign so we don't simply transplant this problem from one location to another."
Iraq's fight to retake Mosul began last October. By November, Iraqi forces had punched into the city limits along Mosul's eastern edge. In January, after 100 days of fighting, eastern Mosul was declared "fully liberated."
All the bridges spanning the Tigris River, which roughly divides Mosul into its eastern and western half, has been destroyed by coalition airstrikes, but residents reported IS fighters still managed to flee west, ahead of the Iraqi advances.
In February, Iraqi forces closely backed by the U.S.-led coalition launched the operation for western Mosul, initially planning to clear it of IS fighters south-to-north. But after the federal police stalled on the southern edge of the Old City just weeks into the push, the joint command center adjusted the plans, ordering Iraqi forces to first sweep up and around the congested Old City.
The slow military approach may be helping Iraqi and coalition forces kill and capture more IS fighters but it has put trapped civilians at greater risk, according to residents who recently fled neighborhoods still in IS hands.
A woman from al-Rifai neighborhood, who fled with her daughter after their house collapsed in an explosion, said her two sisters and their families were still inside the Old City.
It had been weeks since she heard from them, she said, speaking to The Associated Press from a civilian screening center south of Mosul on condition of anonymity, fearing for her relatives' safety.
Smugglers who deliver food into the district told her that months of Iraqi artillery and airstrikes have killed hundreds, she said. "In a single day they buried 30 bodies," she said.
Iraq's military dropped leaflets over the Old City Friday asking civilians to flee "immediately" to "safe passages" where they will be greeted by "guides, protectors and (transportation) to reach safe places," according to a government statement.
But human rights group Save the Children warned the order would likely lead to "deadly chaos" as the Iraqi government has not negotiated safe passage for civilians with IS.
Over the past two weeks IS has begun barricading families inside their homes, said Khaled Ahmed Aziz, also from al-Rifai. He said IS recently welded the doors to his sister's home shut.
"Now, even if she wanted to flee, she cannot," he said.
Ayad Sayyid, a doctor working at a clinic treating civilians fleeing Mosul said as the battle has ground on he is seeing more children and elderly patients suffering from malnutrition.
Last month there were about five cases a week, now he says he sees 20. Mosul residents have been suffering from food shortages for months, a hardship expected to be exacerbated during the holy month of Ramadan that began Friday night, when Muslims fast during daylight hours.
"It's a disaster," he said, adding that even before the battle, the residents of the Old City were among Mosul's poorest.
Since the push on western Mosul began, the United Nations says more than 580,000 people have been forced to flee.
"Please save the Old City as soon as possible," the woman from al-Rifai pleaded. "But, please stop the airstrikes, there are already enough bodies under the rubble."
Associated Press writer Qassim Abdul-Zahra in Baghdad contributed to this report.
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