Unlike some of his bosses, little is known about an Iranian commander the US sanctioned this week for what Washington says was his role in crushing the country’s latest protests. But his area of operations in a troublesome corner for Tehran indicates that General Hassan Shahvarpoor of the Islamic Revolutionary Guard Corps is a main enforcer in the system. Sanctioning Mr Shahvarpoor may signal a widening of US sanctions to include Iranian operatives who are less well-known and further down the political and security hierarchy. Washington said Mr Shahvarpoor was responsible in November for the killing of dozens of protesters in the city of Mahshahr in Khuzestan province. The area is a major oil producing centre and home to many of Iran’s Arab minority, who constitute about 2 per cent of Iran’s population. Khuzestan is also the military sector Mr Shahvarpoor oversees. The area was a major theatre in the Iran-Iraq war which lasted from 1980 to 1988. Saddam Hussein had declared that liberating the region’s “Ahwaz Arabs” from what he termed Iranian subjugation was a major reason for starting the war, in which a million people were killed. Iranian officials stress national cohesion, dismissing ethnic differences US political commentators sometimes point to as indicating latent social instability in Iran. But the commander overseeing a fringe region as sensitive as Khuzestan, would have to be most trusted by the Iranan elite, and likely to be provided with the means to tightly control such a sensitive part of the country. Citing media reports and information “tips” by Iranian citizens, the US State Department said IRGC units commanded by Mr Shahvarpoor killed as many as 148 Iranians. The IRGC, “encircled fleeing protesters in armoured vehicles, firing machine guns into the crowd and lighting fire to the marsh in which the protesters took cover,” it said in a statement on Saturday. The killings in Mahshahr occurred in the context of a crackdown on a protest movement sparked by fuel price hikes. The IRGC, along with other security branches, reportedly killed up to 1,500 people by the time the authorities put down the uprising in December. But Mr Shahvarpoor missions do not appear to be purely domestic. In November he told the pro-regime Fars news agency that 5,000 IRGC troops under his command were deployed at border crossings to protect Iranian pilgrims going to Iraq for the religious ceremony of Arbaeen. The occasion marks the end of 40 days of mourning for the martyrdom of the Prophet’s grandson, Imam Hussein, in 680. Iraqi activists said IRGC members accompanied the pilgrims inside Iraq to the holy city of Karbala. As Iraq’s protest movement, which is demanding the removal of the political class, paused for Arbaeen, the killing of protesters reduced significantly. Iranian demonstrators had no such respite.