MOSUL, Iraq, Nov. 12 (UPI) -- Iraqi forces have encountered stiff resistance from Islamic State fighters as government forces advance into densely populated portions of the city, military officials said.
In addition, Sky News reported an Islamic State killing field and mass grave was found at the site of a former college campus in a town outside Mosul, where as many as 300 mutilated corpses were found buried in shallow graves or left laying to rot in the sun.
The fight to retake Mosul, the largest city still under Islamic State control, has slowed, government forces said, as Iraqi soldiers enter the city's most densely populated neighborhoods, offering IS fighters seemingly endless places to hide, and exposing government troops to difficult-to-defend suicide attacks.
A combination of Iraqi army soldiers, Kurdish Peshmerga fighters, militarized police and autonomous Shiite militias, a fighting force of more than 100,000 in total, has steadily advanced on Mosul. The U.S. military has provided air support for the offensive. In response, Islamic State fighters have dug in their heels, mounting a stiff defense and multiple counter-offensives.
The International Organization for Migration reported this week more than 49,000 civilians have been displaced and hundreds have been slaughtered by IS fighters in the run-up to the battle for Mosul.
Some residents have begun leaving the city on foot, carrying white flags as they approach Iraqi government forces on the outskirts of the city.
In Hammam al Alil, a town south of Mosul, government forces made the gruesome discovery of a mass grave at the site of a former agricultural college. Residents in the area reported seeing individuals marched toward the campus in blindfolds and the sound of frequent gunfire coming from the area.
The United Nations confirmed the mass grave and estimated the number dead there at 100. Locals told Sky the number dead is at least three times higher.
One man, Assad al-Hindi, told Sky News his two nephews, former members of the Iraqi army, were taken to the campus and shot to death. He risked his own life going there to retrieve their bodies under cover of night. The following day, Islamic State fighters beat another family member as he was digging their graves in the town's cemetery.
"My feelings have passed any level of anger," al-Hindi said. "I have reached the state where this is normal. I don't have feelings anymore."