BAGHDAD, Iraq: Holy Kadhimiyah is in profound grief and mourning as the commemoration of the martyrdom anniversary of Al-Imam Mussa Al-Kadhim (AS), the seventh infallible descendant of prophet Muhammad (S), was in climax on Saturday July 18, Rajab 25.

Iraqi security officials said they expected record numbers of Shi'ite Muslims, up to 6 million, to visit the Imam Mussa al-Kadhim shrine in northern Baghdad.

A sea of people, mostly dressed in black, thronged roads leading to the golden domed shrine throughout Friday to observe the sad occasion.

During the pilgrimage, the crowds carry a coffin to show their devotion to the imam.

"We are here today because Imam Kadhim said, 'God bless those who resuscitate our cause,' " said Chasib Kadhim , 45, as he was giving water to pilgrims.

This is the first major security challenge for Iraqi military forces since U.S. combat troops withdrew from Iraq's cities June 30.

"This is the first 100 percent Iraqi security plan. The forces are Iraqi, even the helicopters," said Baghdad security spokesman Major-General Qassim al-Moussawi.

Despite intensive security, some bombers made it through.

The Kadhimiya site has been surrounded by three rings of security personnel to search each pilgrim, and helicopters patrol overhead. Cameras on air balloons monitored the site, the surveillance provided by the U.S. military at Iraq's request.

"I haven't joined the pilgrimage for a while because I was afraid. This is the first time," said pilgrim Ali Hussein.

"This pilgrimage is unprecedented. All the roads are open ... The number expected is higher than in previous years," said Baghdad security commander Major-General in Staff Abboud Qanbar.

"Nothing will prevent us visiting Kadhimiya. We used to come in the days of slaughter, and now you can see the security there's no excuse not to come," said pilgrim Adnan Mohammed.

Authorities have imposed a limited curfew in Baghdad; Around 100,000 policemen were put on alert throughout the capital to try to prevent attacks against pilgrims.

A brigade from the Iraqi Federal Police — previously known as the Iraqi National Police — set up checkpoints at which men, women and children were searched Thursday, and Iraqi army helicopters flew low over the crowds.

Two American helicopters also hovered overhead; in the past, Iraqis had asked that only U.S. helicopters protect their missions.

"The significance of this pilgrimage is to reject oppression, reject tyranny and to show the oppression that occurred against the family of the Prophet," Sheik Fadhil al Daraji said as he walked among the pilgrims "It also helps the society to unite. As you can see, Sunnis and Shiites alike help the pilgrims."

A pilgrim can eat and drink for free all the way to the shrine, and some have come hundreds of miles.

Residents and different mawakeb pitch tents to provide rest for the pilgrims, and cook for them on the sides of the road. The Ministry of Health has moved ambulances to areas where pilgrims might need them.

The Red Crescent, the Islamic world's equivalent to the Red Cross, has deployed hundreds of volunteers at 18 stations on the road to Kadhimiyah to serve the pilgrims and offer resting places and first aid.