Airstrikes, automatic fire and artillery were heard from dawn and one soldier was reported killed in clashes. Civilians, some of them wounded, could be seen fleeing the fighting, AP reported.
According to the officers, the Iraqi forces aim to take complete control of the city's Tahrir area and from there move into the adjacent Muharabeen district.
Iraqi forces launched the long-awaited operation to retake Mosul a month ago but have only advanced into a few eastern districts. The troops have faced fierce resistance, with snipers, mortar fire and Daesh suicide bombers driving armor-plated vehicles packed with explosives.
On Thursday, cloudy skies over Iraq's second-largest city obscured the visibility of the drones and warplanes on which the troops rely, hindering their advance. Instead, special forces secured areas they had seized, set up checkpoints and swept for explosives.
The pause also allowed the residents running out of food in areas liberated from Daesh to get some supplies from Iraqi troops and aid organizations.
The recapture of Mosul would mark the Takfiri militants’ effective defeat in the Iraqi half of the territory they seized in 2014.