Despite threat of Takfiri attacks, millions of pilgrims have for days been streaming through the golden-domed mausoleum of Imam Hussein (A.S.).

Millions of Faithful packed the holy Iraqi city of Karbala on Thursday for the culmination of Arbaeen, one of the world's largest religious events.

Despite threat of Takfiri attacks, millions of pilgrims have for days been streaming through the golden-domed mausoleum of Imam Hussein (A.S), the Prophet Mohammed's grandson who was martyred in 680 AD.

Arbaeen is an annual commemoration of the end of the 40-day mourning period over the martyrdom of Imam Hussein (A.S.).

Many made the pilgrimage on foot from the Iraqi capital, walking along roads lined with blast walls and razor-wire, and waiting at checkpoints to be frisked by security forces. Soldiers and police also mingled with the pilgrims, most of whom wore black out of mourning.

Iraqi officials said security was increased this year, with operations coordinated between the Interior Ministry, and Popular Mobilization forces in a bid to confront any threat by the Takfiri group, ISIL (so-called Islamic State in Iraq and Levant).

Iraqi state-run media said Wednesday that more than 22 million pilgrims have visited Karbala, setting a record for the annual pilgrimage. Iraqi authorities said last year’s Arbaeen drew 17 million pilgrims.

The faithful traditionally walk for a day or longer to reach Karbala where crowds chant and march around the Imam Hussein (A.S.) shrine.

On the walk to Karbala, which can take up to two days, pilgrims said security was the main topic of conversation, closely followed by current politics, the Associated Press reported.