Iraqi security forces fired shots into the air during a pre-dawn clash among themselves on Thursday, ahead of the massive Arbaeen pilgrimage in the holy city of Karbala. The incident, which occurred around five kilometers from Karbala's old city, involved a standoff between the Iraqi army and members of the Hashed al-Shaabi, a pro-Iran Shiite group that has been integrated into Iraq’s security forces, according to security officials.

The altercation began when four vehicles belonging to the Hashed al-Shaabi attempted to pass through an Iraqi army roadblock on a street designated exclusively for pedestrian pilgrims. The army blocked the vehicles from proceeding, resulting in both sides firing shots into the air. Despite the tension, no injuries were reported.

The clash took place as hundreds of thousands of Shiite pilgrims were making their way to Karbala to observe Arbaeen, a significant religious event that marks the conclusion of the 40-day mourning period for Imam Hussein, a revered figure in Shiite Islam and the grandson of the Prophet Mohammed.

Last year, the Arbaeen pilgrimage attracted 22 million participants, many of whom traveled from Iran. This year, official figures indicate that approximately 2.9 million pilgrims have entered Iraq since August 6, with the commemorations expected to reach their peak on Sunday.

Following the clash, six members of the Hashed al-Shaabi were arrested by a security unit within their own organization. An investigation is currently underway to determine who was responsible for initiating the gunfire amidst the gathering pilgrims.

The Hashed al-Shaabi was formed in 2014 to combat the Islamic State group after the regular Iraqi army struggled to contain the jihadist threat. Despite being formally integrated into Iraq's security apparatus, the group remains a powerful political and military force and has experienced periodic clashes with other security institutions.