Hundreds of thousands of Shi'ite pilgrims are gathering in the Iraqi city of Karbala for a religious commemoration, as fears of sectarian violence remain three years after the U.S.-led invasion of Iraq.
Iraqi authorities deployed 8,000 security personnel around the holy city, where as many as two million pilgrims are expected by Monday. They are marking the end of the 40-day mourning period for Prophet Mohammed's grandson, Imam Hussein, killed in 680.
A mortar was fired on the city on Sunday but caused no injuries.
In other violence, Iraqi police say U.S. troops killed eight civilians south of Samarra. And in Baghdad, three bodies were found blindfolded and shot.
The latest violence comes as former Iraqi Prime Minister Iyad Allawi told British television his country is already in civil war.