According to the Astan (custodianship) of Imam Hussein (AS) holy shrine, the huge number has been unprecedented since 2003, Al-Forat News reported.
Fadhil Awaz, an official with the Astan, said the pilgrims are from Iraq and various other countries.
He said pilgrims have been arriving in the holy city since the first day of Muharram (July 30).
Muharram is the first month in the lunar Hijri calendar.
Shia Muslims, and others in different parts of the world, hold ceremonies every year in the month of Muharram to mourn the martyrdom anniversary of Imam Hussein (AS) and his companions.
The third Shia Imam (AS) and a small group of his followers and family members were martyred by the tyrant of his time - Yazid Bin Muawiya, in the battle of Karbala on the tenth day of Muharram (known as Ashura) in the year 680 AD.