They were greeted at the Mashhad railway station.

Arbaeen, which is one of the largest religious gatherings in the world, comes 40 days after Ashura, the martyrdom anniversary of the third Shia Imam, Imam Hussein (AS).

Each year, a huge crowd of Shias flock to Karbala, where the holy shrine of Imam Hussein (AS) is located, to perform mourning rites.

In the past few years, around 20 million pilgrims from all over the world, including Iran, took part in the mourning ceremonies in the Iraqi holy cities marking Arbaeen.

This year, Arbaeen fell on Thursday, November 9.

Al-Mustafa International University is an Iranian academic center with many overseas branches for non-Iranian Muslims who seek to study Islam and related subjects.

The university offers graduate, post-graduate and PhD courses in such fields as Fiqh (jurisprudence), theology, history of Islam and interdisciplinary fields with an Islamic approach.