Violence in Baghdad and southern Iraq killed eight Iraqis, including six Shiite Muslim pilgrims, and an American soldier on Friday, security officials said.
The six killed on the outskirts of the holy shrine city of Karbala, 100 kilometres (70 miles) south of the capital, were making their way there as part of commemorations for the birth of a revered Shiite Muslim figure.
"A car bomb killed three people and wounded 20 people inside a bus station north of the city of Karbala," said General Othman al-Ghanimi, a security official in charge of security in the region.
Nazeer al-Rubayee of Karbala's Al-Hussein Hospital confirmed the toll, saying that the wounded included women. The blast occurred at around 4:00 pm (1300 GMT).
At around 9:30 pm (1830 GMT) east of the city, another car bomb killed three worshippers and wounded more than 25, Karbala health department spokesman Jamal Mehdi said.
Thousands of pilgrims are headed to Karbala to mark Shahbaniyah, the birthday of a revered Shiite Muslim figure, which falls on either Saturday or Sunday, with the dates differing depending on interpretations of the lunar calendar.
In the Dora district of southern Baghdad, one person was killed and three wounded by an improvised bomb, an interior ministry official said.
Meanwhile, in another part of the same district, an explosion in the early hours of Friday killed one person in a house where police later found several improvised bombs and guns fitted with silencers.
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Also on Friday, an American soldier was killed, the fourth such death this month, days after US Defence Secretary Leon Panetta said US troops had resumed attacks against Iran-backed militias.
"A US service member was killed Friday while conducting operations in southern Iraq," said a brief statement by the American military, reporting yet another casualty in the Shiite-majority south that is home to anti-American militias Washington says are backed by Iran.
The statement gave no further details.
The latest death was the 18th casualty in six weeks, after US forces suffered their deadliest month in three years in June, losing 14 soldiers in attacks.
The last US casualty of this month was on Sunday, coinciding with Panetta's surprise arrival in Baghdad, where he expressed "tremendous concern" over Iran-supplied weapons he said were being used to attack troops.
Panetta also disclosed that American forces had resumed pursuing Iran-backed insurgents in Iraq, nearly a year after the US military in Iraq announced a formal end to combat operations.
The violence comes after June was the deadliest month so far this year for the number of Iraqis killed, and the bloodiest in three years for US forces, who lost 14 soldiers in attacks.
Last month, 271 Iraqis died in attacks -- 155 civilians, 77 policemen and 39 soldiers -- according to a government count.
Many of the victims were Iraqi civilian and military officials killed with silenced weapons.