Iraqi security forces advance during fighting against Islamic State militants, in western Mosul, Iraq, Monday, March 6, 2017. Iraqi government forces are reported to have captured further ground after launching a new push against the western part of Mosul. (AP Photo/Khalid Mohammed)

MOSUL, Iraq — U.S.-backed Iraqi forces were fighting their way through a government complex in the heart of western Mosul after storming the buildings in an overnight raid, and were facing fierce counterattacks today from the Islamic State group.

According to Lt. Gen. Abdul-Amir Rasheed Yar Allah, the troops hoisted an Iraqi flag on the complex of buildings in the Dawasa neighborhood earlier in the morning, hailing the federal police units behind the taking of the area as heroes.

By noon, troops on the ground said the complex has not yet been secured and that they are battling a wave of intense IS counterattacks.

Sgt. Azam Ibrahim of the federal police was one of the first troops to storm the Mosul government complex. His unit then pulled back to a base on the edge of Mosul’s Tayran neighborhood, saying the clashes were still underway at the complex later Tuesday.

“We were pulled back because we had killed and wounded,” Ibrahim told The Associated Press. “The (Iraqi) forces there are surrounded, the Humvees cannot reach them, nor can the ambulances.”

The consistent advance — more than two weeks since the new push started to clear Mosul’s western side of IS militants — has been a major blow to the extremists who once controlled nearly a third of Iraq.

Iraqi forces declared eastern Mosul “fully liberated” in January after officially launching the operation to retake the city in October

Yar Allah, who commands the army operations in Ninevah, where Mosul is the provincial capital, said the troops now also control the western side of a second bridge across the Tigris River, known as Hurriyah Bridge.

Last week, the troops reached the first bridge from the south in western Mosul, known locally as the 4th Bridge. U.S.-led airstrikes disabled all of Mosul’s five bridges last year in a bid to isolate the militants.

Hours after announcing today’s advance, Iraqi state TV said Prime Minster Haider al-Abadi visited the troops in Mosul. Al-Abadi was shown descending from a military plane at the city’s airport and meeting with senior military officers. It was unclear if al-Abadi visited the western part of Mosul.