A roadside bomb killed a U.S. soldier and two children in Baghdad on Sunday. The Baghdad blast also injured five U.S. troops and their Iraqi interpreter as well as eight members of the Iraqi civil defense corps, said U.S. Army Sgt. Patrick Compton of the Army's 1st Armored Division. Elsewhere, a bomb exploded west of Baghdad, killing another U.S. soldier and wounding three others, the military said. The soldier who was killed was in a convoy near Fallujah, west of Baghdad. The three wounded soldiers were evacuated. Meanwhile, the deputy security chief of the Kurdistan Democratic Party (KDP) was wounded and his three bodyguards killed in an ambush Sunday outside his home, police said. The KDP number two security official Jawamir Attiyah Kaki was rushed to hospital, said Arbil's police chief Nariman Abdel Hamid, AFP reported. In Karbala, a health department official said five more Iraqis died on Sunday after being wounded in Saturday's bomb attacks in the city. "Five people, including a woman, later died from their injuries, raising the toll to 12 Iraqis," said the city's top health official Saad Nasrawi, according to AFP. Six occupation soldiers -- four Bulgarians and two Thais -- were also killed in the multiple attacks around Karbala that left more than 120 wounded. Iraqi and US officials suspected the involvement of foreign fighters in the attacks. "An investigation to identify the authors of the attack is underway and we think that some of them came from inside the country and that others came from outside," said Hamid al-Kifai, a spokesman for Iraq's interim Governing Council. **PHOTO CAPTION*** Iraqi boys check out a car that was overrun by a U.S. tank in the town of Samarra, Iraq, Sunday, Dec. 28, 2003. (AP Photo/Hadi Mizban