Ali Hosein Hoseinzadeh, deputy governor in Khuzestan province, was quoted as saying the death toll was expected to rise. One of those killed was a journalist. The bloodshed struck a blow to security in OPEC oil producer Iran, which has been relatively stable compared with neighbouring Arab countries that have grappled with upheaval since the 2011 uprisings across the Middle East. There was no immediate claim of responsibility for the attack in the city of Ahvaz.