Iran leads off the war on ISIS in Fallujah

US commandos are on the front lines in Syria in a new push toward the Islamic State’s de facto capital in Raqqa, but in Iraq it is an entirely different story: Iran, not the United States, has become the face of an operation to retake the jihadi stronghold of Fallujah from the militant group.

On the outskirts of Fallujah, tens of thousands of Iraqi soldiers, police officers and Shiite militiamen backed by Iran are preparing for an assault on the Sunni city, raising fears of a sectarian bloodbath.

The battle over Fallujah has evolved into yet another example of how US and Iranian interests seemingly converge and clash at the same time in Iraq. Both want to defeat the Islamic State. But the United States has long believed that Iran’s role, which relies on militias accused of sectarian abuses, can make matters worse by angering Sunnis and making them more sympathetic to the militants.

Inside the city, tens of thousands of Sunni civilians are trapped, starving and lacking medicine, according to activists and interviews with residents. Some were shot dead by the Islamic State as they tried to flee, and others died in buildings that collapsed under heavy artillery bombardment in recent days, according to the United Nations.

In an extraordinary statement last Wednesday, Grand Ayatollah Ali al-Husseini al-Sistani, the world’s pre-eminent Shiite religious leader, who is said to be concerned by Iran’s growing role in Iraq, urged security forces and militia to restrain themselves and abide by “the standard behaviours of jihad”.

The grim sectarian tableau in Fallujah – starving Sunni civilians trapped in a city surrounded by a mostly Shiite force – provides the backdrop to a final assault that Iraqi officials have promised will come soon.

The United States has thousands of military personnel in Iraq and has trained Iraqi security forces for nearly two years, yet is largely on the sidelines in the battle to retake Fallujah. It says its air and artillery strikes have killed dozens of Islamic State fighters, including the group’s Fallujah commander.

But it worries that an assault on the city could backfire – inflaming the same sectarian sentiments that have allowed the Islamic State to flourish there.