Iraqi police and army troops stormed the ISIS-held town of Hammam al-Alil Saturday, in an attempt to drive militants from the last major Iraqi stronghold, according to CNN.
This long-awaited assault is meant to put pressure on ISIS fighters.
Troops are approaching and surrounding Hammam al-Alil, which is located about 18 miles south of Mosul, on three fronts.
WATCH| Here's the latest on the Mosul offensive
Friday, the UN refugee agency reported that ISIS is using Hammam al-Alil boys ages 9 and older in the fight against Iraqi forces.
Iraqi Prime Minister Haider al-Abadi recently issued a warning to the terror group saying: "If they want to save their lives, they should lay down their weapons now. We will punish the criminals among them, and we will hold them to account."
ISIS fought back Saturday
ISIS fought back, pushing Iraqi special forces from the southern edge of Mosul Saturday. Both fired off mortar rounds as snipers dueled on the rooftops of the residential areas.
Dozens of civilians fled their homes, walking more than 6 miles to the nearest camp for those displaced by the fighting.
Prior to the Mosul offensive, Iraqi forces developed a plan to reduce civilian casualties.
We've never been in such a situation before. We would be fighting and there would be a family right next to us.
Iraqi Cpt. Naqib Jaff, said that in previous operations against ISIS, civilians were evacuated from the front lines. In this case, however, Jaff and his men have been ordered to keep families inside.
The government has asked residents not to leave, fearing the more than 1 million people left in Mosul would try to flee all at once.
Despite this, thousands of civilians have been forced from their homes.
The UN refugee agency reported Friday that it had received 3,000 at a new camp for those fleeing violence. Many have fled from the eastern outskirts of Mosul, according to CNN.
The Associated Press contributed to this report.