A car bomb exploded on a route taken by pilgrims returning from commemorations for a revered Shiite imam in Baghdad on Saturday, killing at least eight people, security and medical officials said.
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 15.
A medical source said that the Kadhimiyah and Al-Hakim hospitals had received 21 wounded people and the bodies of nine others between them.
The attack came as tens of thousands of Shiite pilgrims flocked to the Kadhimiyah area of the city for the climax of commemorations marking the death in 799 of Imam Musa Kadhim, the seventh of 12 revered Shiite imams.
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 left 16 people dead.
Along with the security forces, the Shiite majority in Iraq has been a main target of Sunni Arab armed groups since the fall in 2003 of Saddam Hussein'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.