City police chief Brig. Burhan Wasif told the Xinhua news agency in Baghdad by telephone two of the dead were policemen serving as bodyguards.

"A suicide bomber rammed his explosive-laden car into the convoy of Brig. Khattab Omer while he heading to his work at about 7:30 a.m.," Wasif said.

There were conflicting reports about Omer's condition, with some saying he was critically injured and others saying he received minor injuries.

In Baghdad, the U.S. military released a statement saying two of its soldiers had been killed in separate incidents Wednesday, Kuwait's KUNA news agency reported.

Both incidents happened in Diyala province, northeast of Baghdad, The first was a bombing that killed one soldier and wounded four others. Hours later, a second bomb killed another soldier and wounded five others, the report said.

Since the March 2003 U.S. invasion, 3,865 U.S. soldiers have died in Iraq.