MOSUL: Iraq's special forces say they are still struggling to clear neighborhoods retaken from the Islamic State group along Mosul's eastern edge.

Lt. Col. Muhanad al-Timimi says Sunday that elaborate defenses built by IS and the presence of civilians have slowed progress.

The civilians make it more difficult for Iraqi commanders on the ground to get requests for U.S.-led coalition air strikes cleared. Iraq's special forces are some of the country's best troops, but they largely rely on air support.

Iraqi forces first entered the eastern edge of Mosul on Tuesday. On Friday, forces began pushing into Mosul proper, but so far have only advanced into the city just over a kilometer (mile).

On the city's southern front Iraqi forces are still some 20 kilometers from the city center.