General Abdulamir Yarallah, the commander leading the offensive to retake Tal Afar, said in a statement on August 26 that government troops had recaptured the city's center and its citadel.
Clashes were ongoing on the northern outskirts and Iraqi forces were dealing with final pockets of terrorists inside the city, Yarallah said.
On Sunday, Iraqi Prime Minister Haider Abadi announced the beginning of the military offensive aimed at retaking Tal Afar, which is located 30 miles away from recently liberated Mosul.
Tal Afar is the latest objective in the USA -backed war on the jihadist group following the recapture in July of Mosul, where it declared its self-proclaimed caliphate over parts of Iraq and Syria in 2014.
Gen. Yahya Rasool said units from the joint Iraqi forces are in full control of 60% of the "operational area" and 90% of the city center of Tal Afar.
On Thursday, U.S. Army Col. Ryan Dillon, the spokesman for the coalition in Iraq, said the militants are "completely surrounded" in the town of Tal Afar and "are being killed".
A predominantly Turkmen district, Tal Afar was overrun by Islamic State of Iraq and the Levant fighters in 2014.
IS still controls large areas in Syria and a handful of towns in Iraq.
Tal Afar has always been a stronghold for hard-line Sunni insurgents.
Ibrahim al-Jaafari made the announcement at a news conference with his French counterpart on Saturday.
The International Organization for Migration said "thousands of civilians" had fled Tal Afar since the offensive began. It was cut off from other IS-held territories in June during the Iraqi-led operation to recapture Mosul. Those remaining are threatened with death by ISIL, according to aid organisations and residents who managed to flee.