BAGHDAD (AP) — Islamic State group militants have blocked the area around a highly symbolic mosque in Mosul's Old City where the group's leader made his first and only public appearance, a resident said on Thursday, as U.S.-backed Iraqi forces pushed to recapture the city's remaining pockets.

The militants have ordered families living near al-Nuri mosque — also known as the Great Mosque — to leave their houses and sealed all the roads leading to it, said the resident who lives in the IS-held sections of Mosul.

Abu Bakr al-Baghdadi delivered a Friday sermon in al-Nuri mosque in 2014 after IS seized almost a third of Iraq and declared an Islamic "caliphate" on territory it controlled in Iraq and neighboring Syria.

The iconic 840-year-old "Crooked Minaret," which leans somewhat like Italy's Tower of Pisa, survived destruction by IS militants as residents formed a human chain to protect it when the militants came to blow it up. The extremists demolished dozens of historic and archaeological sites in and around Mosul, saying they promote idolatry.

"The militants are not moving in groups anymore, we see one or two from time to time in the streets as a majority of them are moving through the houses, using the holes they made in the walls," he said. He spoke to The Associated Press on condition of anonymity for fear for his safety.

According to U.N. estimates, more than 100,000 people are still trapped in their houses in IS-held areas. Mosul's Old City is an ancient district of narrow alleyways and tightly packed homes, two main challenges to security forces.

"We are dying slowly with no water and no food," the resident said of the deteriorated situation in their areas.

The Iraqi government launched last October launched a wide-scale military offensive to recapture Mosul and the surrounding areas, with various Iraqi military, police and paramilitary forces taking part in the operation. The city's eastern half was declared liberated in January, and the push for the city's western section, separated from the east by the Tigris River, began the following month. Since then, IS hold on Mosul has shrunk to just a handful of neighborhoods in and around the Old City district.