'All the injured have been transferred to Iran and four of them who were in serious condition were transferred to Kermanshah hospital by helicopter ambulance,' Head of Iran’s Emergency Medical Services Pir-Hossein Kolivand told Islamic Republic News Agency (IRNA) on Saturday.

Axar.az reports citing IRNA that Iranian pilgrims were travelling from Tehran to the city of Najaf to attend the Arbaeen mourning ceremony.

Arbaeen, falling on November 9 this year, is a Shia Muslim religious observance that occurs forty days after the Day of Ashura to commemorate the martyrdom of Imam Hussein (AS), the grandson of Prophet Mohammad (PBUH) and the third Imam of Shia Muslims.

Each year, millions of pilgrims, mainly from Iraq and Iran, travel long routes on foot to Karbala, where the holy shrine of Imam Hussein (AS) is located.