Four Iraqis were killed when a US convoy opened fire on their car in northern Iraq as three US soldiers were confirmed dead in separate insurgency attacks. Local police said the Iraqis, including a woman and a child, were killed when a US convoy opened fire on their car in the northern town of Tikrit. "The car, a gray Chevrolet Caprice, was hit by 27 shots and skidded, resulting in the death of four people, including a woman and a nine year-old child," Tikrit police chief Colonel Ussama Adham Abdel Ghaffer said. US Lieutenant Colonel Steve Russell, head of the 4th Infantry Division battalion that patrols the area, said he was aware of a shooting incident involving a civilian car, but stressed his men were not involved. But a fifth person who survived the incident with chest wounds also said the vehicle had taken fire from a US convoy. A US soldier was killed Friday in an attack at Balad, 75 kilometres north of Baghdad, shortly after insurgents in the volatile western town of Fallujah shot down a US helicopter killing at least one soldier. Sergeant Robert Cargie, a spokesman for the 4th Infantry Division, said the Balad attack occurred at about 5:00 pm and that the soldier was struck by shrapnel from a mortar exploding inside a military base. Two soldiers were also killed and three wounded Friday at 12:00 pm (0900 GMT) when their patrol hit a roadside bomb south of Baghdad, the US military said Saturday. The US military said Saturday it arrested 128 suspects and seized large quantities of arms and explosives during 24 hours of raids across western Iraq. Iraqi police said six suspects, including a Yemeni and an Afghan, had been arrested by US troops and weapons seized near the restive town of Baqubah, north of Baghdad. Meanwhile, media reports said Saturday that three of its personnel arrested at the scene of the Fallujah helicopter crash were still in US custody and no reason had been given for their detention. US Brigadier General Mark Kimmit said the downed helicopter was fired on after the attack by people wearing jackets labelled "press" and four were later arrested. It was not clear if these included the Reuters staff. In the northern Iraqi oil centre of Kirkuk, where ethnic rivalries erupted into violence earlier this week and left seven people dead, six people were injured in separate shooting incidents. A Kurd was wounded when his car came under gunfire on Saturday night, police said adding that it fired at the assailants and wounded them too. Two Iraqi Arabs who attempted to attack police were lightly injured when officers opened fire, police said. A Turkmen security guard was also injured when unknown assailants opened fire on a Turkmen political party headquarters. **PHOTO CAPTION*** US soldiers from the 1st Battalion, 22nd Regiment of the 4th Infantry Division fire mortar while as part of a practice to keep up their skill at their base in Tikrit. (AFP/Jewel Samad)