Two men - Hossein Karimi Yeganeh, 28, and Bahman Rezaie, 25 - have been killed and two other people wounded in a drive by shooting in the Iranian town of Dezful in Khuzestan province, during Shia commemorations of Ashura on Friday night, the official IRNA news agency reported.
"It's not still clear whether the attack was a terrorist one," police official Colonel Rahman Mousavi said, adding that they are investigating the incident.
The car which the attackers used to carry out the attack had no license plates.
Khuzestan shares a border with Iraq and has a significant number of Arab residents, some of whom are Sunni and Iranian. The media reported that the province has seen a number of attacks in recent years.
A similar attack took place in Saudi Arabia on Friday night in where five people were killed after a gunman opened fire on a Shiite Muslim meeting hall. Saudi media sources blamed ISIS for the attack.
Ashura, the 10th day of Muharram -first month of Hijri Calendar- is on October 23 this year. It is an important day of commemoration and mourning among Shia Muslims. The grandson of Prophet Muhammad, Hussein ibn Ali was martyred on that day in Karbala.