More than two million Shiite Muslims from across the Middle East swarmed the shrine city of Karbala in central Iraq on Wednesday for the climax of the annual Ashura ceremonies amid tight security.
Wailing men and even young boys in flowing white robes marched with blood streaming down their faces after slashing their scalps open with knifes in a ritual that commemorates an imam slain 13 centuries ago.
Accompanied by drummers and horn players, other pilgrims pounded on their chests and whipped their backs with metal chains as part of the devotional self-flagellation that characterises Ashura.
The focus of the pilgrims in the desert city of Karbala, 100 kilometres (62 miles) south of Baghdad, were two gold-domed holy shrines -- one to Imam Hussein and the other to his half-brother Imam Abbas.
More than two million pilgrims from across Iraq as well as from Iran, Bahrain, Saudi Arabia, Kuwait, Oman, Pakistan and Tanzania have streamed into Karbala, said Sheikh Nameh al-Salman, a city official.
The rituals, which began 10 days ago and reached a frenzied pinnacle on Wednesday, mark the holiest days for Shiites in a commemoration of the death of Imam Hussein, who was killed by the armies of the Sunni caliph Yazid in 680.
Tradition holds that Hussein, grandson of the Prophet Mohammed and the third of 12 imams in Shiite Islam, was decapitated and his body mutilated by Yazid's armies.
To show remorse for not saving Hussein, Shiite volunteers whip themselves with metals chains while some cut their scalps with knives as they chant his name on the way to the two shrines.
Second only to the pilgrimage to Mecca in Saudi Arabia, the pilgrimage is the most important religious event for Shiite Muslims, and despite its sombre tone pilgrims are overcome with devotional emotion.
"We are here because of our belief and we are trying to do something so that Hussein will triumph in the end," said a 45-year-old pilgrim, blood streaming down his face, who gave his name only as Jawad.
Basheer Najem, 46, another pilgrim, proudly showed off his bleeding head.
"I have been doing this for the past nine years. I don't feel any pain. After doing this I feel that have I fulfilled my duty."
After prayer, the pilgrims were to perform a spectacular race in Karbala between the mausoleums of Hussein and his half-brother Abbas, known as the "Twarij" and the last symbolic act of the pilgrimage.
The organisers have poured sand in the mausoleums so the pilgrims will not slip on the stone slabs.
But the swarming crowds pose a serious security challenge as in the past the ceremonies have made for easy targets for Sunni insurgents, prompting officials to mobilise 30,000 extra police.
Security was also tight for Ashura rituals in the capital baghdad, where a female suicide bomber blew herself up in a crowd of pilgrims queuing at security gates leading to an important Shiite shrine, killing 35 people and wounding dozens.
Officials in Baghdad have taken the unusual step of banning women from the Musa Kadhamiyah shrine in the north of the Iraqi capital until the end of Ashura.
Major General Qassim Atta, Iraq's spokesman for security in Baghdad, said the decision to ban women from entering the area was aimed at facilitating the flow of people.
"Searching women takes much longer. That is why we took this decision to prevent women from outside Kadhamiyah entering," he told AFP during a security tour of the area.