Brig. Gen. Haider Fadel of the special forces told The Associated Press that Daesh fighters were targeting his forces with rockets and mortars as they slowly advanced in the densely populated Zohour neighborhood.

"We are cautiously advancing. There are too many civilians still living there," he said.

Iraqi troops began their siege of Zohour on Sunday as they fortified their positions in neighborhoods they had already retaken in eastern Mosul. Suicide bombings, sniper fire and concerns over the safety of civilians – there are 1 million civilians still in Mosul – have combined to slow down progress in the campaign to liberate the city, which began Oct. 17.

Mosul was captured by Daesh in the summer of 2014. It is Iraq's second-largest city and the last major Daesh urban bastion in the country. Most gains in the campaign so far have been made by the special forces operating east of the Tigris River. Other forces, including the Kurdish Peshmerga troops and volunteer Sunni militiamen, are advancing on the city from different directions.

The officers spoke to the AP on condition of anonymity because they were not authorized to speak to the media.