March 20 (UPI) -- Iraqi security forces are less than 1,600 feet away from Mosul's Great Mosque of al-Nuri, or Noor mosque, where leader Abu Bakr al-Baghdadi is believed to have declared the Islamic State.
The Iraqi army, with the support of helicopters, advanced into the Old City of Mosul and an area near the mosque on Sunday. Iraqi Federal Police Lt. Gen. Haidre Yusuf Abdulla said Iraqi forces are using extra caution to protect civilians and the Old City's ancient structures.
The Islamic State is putting up a fierce resistance while defending positions in western Mosul's densely populated areas, Abdulla said.
"It is one of the toughest areas, and in fact it is difficult, chaotic and very tight, but our forces managed to get out of their vehicles and enter the Old City," Abdulla added.
Mosul's Great Mosque of al-Nuri is where Islamic State leader Baghdadi is believed to have delivered a sermon in which he declared an Islamic State caliphate. Construction of the mosque was completed in the year 1172.
Brig. Gen. Abbas al-Juburi, a commander with the Iraqi Rapid Response Division, said the Islamic State is using civilians as human shields as they also use suicide bombers to hold off the advance of Iraqi forces.
"The challenges are, firstly, how to avoid hitting civilians because they are using them as human shields," Juburi said. "And secondly, the area is difficult because it is in an ancient neighborhood and we use less heavy weapons."
The United Nation's International Organization for Migration on Sunday said 116,256 civilians have fled west Mosul since Feb. 25. More than 750 civilians have been killed or injured since the battle for west Mosul began over a month ago, Rudaw reported.
Iraq launched its military offensive to retake western Mosul from the Islamic State, also known as Daesh, ISIL and ISIS, on Feb. 19. The offensive to retake Mosul began Oct. 17, led by Iraqi security forces and aided by the Kurdish Peshmerga, a Shiite-led militia, and the U.S.-led international coalition. Iraq fully captured east Mosul in late January.