HAWIJA, Iraq — The initial push into the Sunni city of Hawija as part of anti-Islamic State operations on Oct. 4 was spearheaded by a Shiite-led Popular Mobilization Units (PMU) force known as the Ali al-Akbar Brigade, according to both locals and the leaders of the group itself.

Al-Monitor accompanied the Ali al-Akbar Brigade on Oct. 5 as it cleared the city center and several residential areas with tanks and infantry, meeting only a few snipers and suicide attackers.

Invocations of historical figures revered by the Shiite sect were ubiquitous, from the Ya Hussein flags flying from tanks to the cries of "Ya Zahra" as Shiite fighters from southern Iraq and turbaned clerics accompanying them ran across streets that were open to sniper fire.

The Ali al-Akbar Brigade is one of the units associated with the Shiite holy shrines in the south of Iraq. It was created in response to Ayatollah Ali al-Sistani’s 2014 fatwa calling on Iraqis to take up arms against IS, in contrast with many of the other Iranian-funded armed groups that had existed in some form prior to it.