Hundreds of thousands of Shiites marched to a gold-domed mosque in harsh heat and sun on Thursday in a pilgrimage of devotion to an 8th century saint that also starkly demonstrated their political power.
Only scattered strikes by Sunni insurgents marred the day, which was held amid tight security to avoid the attacks that have occurred during past gatherings.
"Long live Moqtada!" some pilgrims shouted as they paraded toward the Imam al-Kadhim shrine, referring to radical Shiite leader Moqtada al Sadr, whose Mahdi army is accused of death squad attacks. "May God kill his enemies!"
A few shook their fists at US soldiers standing alongside the procession route, but the march was mostly peaceful.
Many said they intended their presence to show they could not be intimidated by Sunni insurgents who have devastated past gatherings, and who regularly target Shiites at markets and on buses.
"I have come here to get the blessing of the martyr imam and to challenge the terrorism of the Wahhabists," said Hussein Mizaal, a 21-year-old college student from southeastern Baghdad -- referring to the austere Wahhabi strain of Sunni Islam. It is practiced mostly in Saudi Arabia but also identified with Sunni insurgents.
"We are not afraid of anyone except God," Mizaal said.
The march comes as Iraq's government remains sharply divided, unable to meet key US-sought benchmarks like a new oil law. Iraqi Prime Minister Nouri al-Maliki, a Shiite who heads the unity government but is accused of bias by Sunnis, was in Iran to talk about security and electricity deals.
Separately, the US military announced two Marines had died in Anbar Province west of Baghdad -- one in fighting and the other in a non-combat incident. Both died on Tuesday. A Multi-Division Baghdad soldier died of non-combat causes.
In addition, two British soldiers were killed early on Thursday by a roadside bomb in southern Iraq, north of the Rumaylah oil fields, the Ministry of Defense said.
At the meetings in Tehran, Iranian officials told al-Maliki they were doing all they could to help stabilize his nation, but insisted that only a US pullout would bring true peace.
Al-Maliki told reporters later that he did not discuss the issue of US forces with the Iranians.
In Baghdad, the heat soared to 46.1oC as the event unfolded.
Residents used garden hoses to spray cool water over pilgrims, many of whom began their journey -- on foot -- days ago from Shiite cities in southern Iraq. Men draped wet towels over their heads and necks.
Guards checked pilgrims as they reached the green iron gates of the mosque, but in some spots the crush of the crowd was so thick that chaos reigned.
A citywide driving ban also was in effect until early Saturday to prevent suicide car bombings. It also improved Baghdad air quality.
Nevertheless, there were scattered attacks: Seven pilgrims were killed when gunmen in a speeding car opened fire and threw hand grenades at them in the Dabouniya area, southeast of Baghdad, as they headed to the pilgrimage, Kut police said.
Gunmen also opened fire on Iraqi soldiers guarding pilgrims in the Yarmouk neighborhood in western Baghdad. The soldiers returned fire, killing one attacker.
The same festival was struck by tragedy two years ago, when an estimated 1,000 pilgrims were killed in a stampede over a bridge after panic that a suicide attacker was among them. And last year, snipers killed at least 20 people as the pilgrims walked through Sunni areas.
This year, some marchers beat their heads and chests with their hands, while others flogged themselves with iron chains in ritual self-flagellation, as loudspeakers played religious music across the city of some 6 million people.
Iraqi officials estimated the crowd at 3 million but verification of the numbers was impossible.
More than 1,800 Iraqi security forces were guarding the mosque complex, including 625 agents inside the shrine, officials said. Shiite militiamen also were throughout the area.
US troops took a lower-key security role, staying away from the area immediately around the mosque to show respect.
Along the Tigris River, residents used dinghies and small motor boats to shuttle pilgrims over the brown churning waters.
"We have so many problems with security, with water and with power in this country -- it's overwhelming," said Imad Muhi, 35, who was helping to bring some of the pilgrims over the river. "This is the one day when we take time out from our own suffering to mourn and celebrate this religious festival."