Shaikh Zaid Khalifa Muhsin al-Bani-Wais was killed late on Thursday as he drove through his hometown of Sadiya, 40km northeast of Baghdad, said Master Sergeant Robert Powell.
Al-Bani-Wais served on the local city council set up by US forces, Powell said, adding that the Americans considered him a "moderate".
It was the latest assassination of a local leader after a tribal chief, Hazim Daraa, was shot in the city of Tikrit on Wednesday night.
Although the attacks could be linked to tribal leaders' ties to the Americans, some of the violence in post-Saddam Hussein Iraq is rooted in power struggles among tribal factions, according to military officers.
In Duluiya, 70km north of Baghdad, an Iraqi was killed and four others wounded in clashes between fighters and the national guard.
And on the road between Samarra and Tikrit, a child was killed and three others wounded in a roadside bomb, medics in the nearby town of Samarra said.
Meanwhile, a police station and the governor's mansion in Bahruz, just south of Baquba, were hit by small arms and mortar fire early on Friday without causing casualties, Powell said.
Three Kurds working for the Kirkuk water and sewerage authority were kidnapped and a fourth wounded while they were travelling back to the city from Baghdad, said an official from the Patriotic Union of Kurdistan (PUK) party.
Several cities across Iraq have
They were allegedly ambushed by fighters posing as Iraqi national guardsmen at a checkpoint near Sulaiman Baigh, 80km south of Kirkuk, said Ramadan Rashid.
Anwar Amin, commander of the Iraq National Guard in Kirkuk, said a car bearing a licence plate from the main Kurdish town of Arbil was also shot at, wounding some of the occupants, who were from the same family.
And in the city of Ramadi, 100km west of Baghdad, US marines reported that the local mayor's office was dynamited.
Prominent shaikh killed
Aljazeera learned that Shaikh Muwafaq al-Duri, a member of the influential Muslim group Association of Muslim Scholars (AMS) was shot dead by US soldiers during a raid they carried out on his house in al-Amiriya neighbourhood, west of Baghdad.
The incident occurred on Friday afternoon while al-Duri was heading to perform Friday prayers at the Abu Bakr al-Sidiq mosque in al-Radhwaniya suburb, south of Baghdad.