Iraqi Popular Mobilization Forces (P.M.F.) commanders say their paramilitary forces are actively participating in the recently-launched military operation to liberate the city of Tal Afar from the Islamic State, the Iranian media report. The Badr Organization, a powerful Iranian-supported P.M.U. group, announced on Sunday that its forces have captured “mountainous regions” in northwestern parts of Tal Afar. A report in Fars News Agency, which is affiliated with the Islamic Revolution Guards Corps, said P.M.F. forces in cooperation with the Iraqi Federal Police recaptured four regions in Tal Afar on the first day of the operation. P.M.F. Spokesman Ahmed al-Assadi also reiterated that the paramilitary forces closely coordinate their operations with the Iraqi security forces. Assadi had previously revealed that as many as 20,000 P.M.F. fighters are expected to participate in the Tal Afar operation.

Akram al-Kaabi, the leader of another Iranian-backed P.M.U group called Harakat al-Nujaba, also boasted about the paramilitary forces’ participation in the operation. “Despite international pressures – particularly by America, Turkey and Saudi Arabia – Hashd al-Shaabi [P.M.F.] will play an extensive role in the operation to liberate Tal Afar,” he was quoted by Fars News Agency as saying.

Comment: On Sunday, Iraqi Prime Minister Haider al-Abadi announced the start of an offensive to retake Tal Afar, a city about 40 miles west of Mosul. The city is strategically important as it lies on a supply line between Mosul and Syria.

Tal Afar has been a major Islamic State stronghold since 2014. Once inhabited by both Sunnis and Shiites, the population in the Turkmen-majority city is now largely Sunni.

The participation of P.M.F. – which are dominated by Shiite groups supported by Iran – in Tal Afar operation has been a matter of concern for Iraqi Sunnis and regional Sunni leaders, who have repeatedly expressed the worry that Iran-backed sectarian groups may engage in revenge killings against Tal Afar’s Sunni inhabitants once the Islamic State is ousted. Turkey, in particular, has warned that it would not remain silent to the P.M.F.’s advances into Tal Afar – although Ankara has recently toned down its criticism of the role of Iran and its proxies in Iraq.

The P.M.F.’s potential participation in Tal Afar operation may have serious implications for post-Islamic State stabilization efforts in Iraq as well, as the city could yet again turn into a dangerous flashpoint for sectarian violence and proxy wars between regional countries.

The news also comes at a time that tension between P.M.F. units and the leadership of Iraqi Kurdistan Regional Government (K.R.G.) is escalating in the run-up to the latter’s plan to hold an independence referendum next month.