In December, more than 50 pilgrims died in a series of bombings in the city, 50 miles south of Baghdad, and in March 2004 at least 181 people died in coordinated bombings of Shiite pilgrims in Karbala and Baghdad. Both attacks were blamed on Sunni extremists.
The explosives cache near Karbala was discovered last night on farmland, police said. Three "non-Iraqi Arabs" were arrested, police said, along with a man armed with several hand grenades who was caught walking with a procession of pilgrims.
Officials said they expected more than a million people to gather today for celebrations marking the birth in 868 A.D. of the 12th imam, Mohammed al-Mahdi, who vanished without explanation. Shiites believe he will return.
Meanwhile, insurgents assassinated a Kurdish member of parliament and police found 20 bodies shot to death and dumped in the Tigris River north of the Baghdad, where there was no major violence yesterday for the first time in five days.
Faris Nasir Hussein, a member of the Patriotic Union of Kurdistan party, was killed along with his brother and their driver in an ambush 50 miles north of Baghdad.
In other developments:
---The U.S. military said a soldier was killed in a roadside bombing while on patrol near Al Asad Air Base. The soldier was assigned to the 56th Brigade Combat Team.
---Government officials announced that one of Saddam Hussein's nephews was sentenced to life in prison for funding the insurgency, and would stand trial on other charges. Officials had not announced that Ayman Sabawi was on trial before revealing that he had been convicted and sentenced to life in prison "for funding militants and possessing and manufacturing roadside bombs."
Sabawi, the son of Saddam's half brother Sabawi Ibrahim al-Hassan, who served as a presidential adviser before the U.S.-led invasion, was captured in early May.