A car bomb killed at least eight people on a route taken by pilgrims returning from commemorations for a revered Shiite imam in north Baghdad on Saturday, marring a ritual attended by tens of thousands.
An interior ministry official said the bomb, which exploded on the highway near Shuala in the north of the capital at about 12:15 pm (0915 GMT), killed eight people and wounded 18.
A medical source said that the Kadhimiyah and Al-Hakim hospitals between them had received 21 wounded people and the bodies of nine others.
The attack came as tens of thousands of Shiite pilgrims flocked to the Kadhimiyah area for the climax of commemorations marking the death in 799 of Imam Musa Kadhim, the seventh of 12 revered imams, who is said to have been poisoned.
On Wednesday, 72 people were killed and more than 250 wounded in bomb and gun attacks across the country, with Al-Qaeda's local affiliate, the Islamic State of Iraq, claiming responsibility.
Those attacks included a car bomb on the outskirts of Kadhimiyah that killed seven people, and another blast in Karrada in central Baghdad amid pilgrims' food tents that caused 16 fatalities.
Saturday’s ceremonies began about 8:00 am (0500 GMT) at the shrine, with a religious leader telling the story of the imam, while people in the crowd wept.
Pilgrims then paraded an empty coffin symbolizing the imam, repeating religious chants, as some hit their chests and heads with their hands in a sign of mourning.
“More people are attending the commemoration this year than in previous years,” said Karim Mohammed, 52. “When we... see that there are explosions, it becomes a challenge to us, so those who decided not to go will go.”
Mohammed, who said he had walked for three days from Samarra, 110 kilometers (70 miles) north of Baghdad, had smeared mud on his face and is black robe in a sign of mourning.
“The imam is the symbol of martyrdom for Muslims in general, and especially for Shiites,” said Abdullah Kitawi, 42, who said he walked for four days from Kut, 160 kilometers (100 miles) southeast of the city.
“Our mission is to preserve this commemoration as long as we live.”
Security measures in Kadhimiyah were tight, with anti-terrorism Special Forces deployed. Pilgrims were searched at various points, as helicopters clattered overhead.
Shiite pilgrimages were prohibited under the rule of Saddam Hussein, but they have attracted huge numbers of people in the years since his overthrow in 2003.
Along with the security forces, the Shiite majority in Iraq has been a main target of Sunni Arab armed groups since the fall of Saddam's Sunni-dominated regime.
Violence has declined dramatically since the 2006-2007 peak of sectarian bloodshed, but attacks remain common, especially in Baghdad. A total of 132 Iraqis were killed in May, official figures show.