A car bomb targeting Shiite pilgrims in Iraq killed three people and wounded 25 others on Saturday, during major Shiite religious commemorations, officials said.
The bomb exploded about 1:30 pm (1030 GMT) at a restaurant where three buses carrying pilgrims were parked on a highway near Balad, north of Baghdad, a police officer said.
Jawad Abdul Kadhim, the head of the Balad hospital, said the attack killed an Iranian woman and two Iraqi men and wounded 25 people, including Pakistanis.
The pilgrims were on their way to visit the Al-Askari shrine in Samarra, which militants bombed in February 2006 sparking a wave of sectarian violence that killed tens of thousands of people.
The attack comes during the Ashura religious commemorations marking the death of Imam Hussein, who was killed by armies of the caliph Yazid in 680 AD.
Tradition holds that the revered imam was decapitated and his body mutilated. Hussein's body is buried in Karbala, 100 kilometres (60 miles) south of Baghdad. His death was a formative event in Shiite Islam.
Millions of people flood Karbala for the peak of the Ashura rituals, which occurs on November 25 this year.
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.