Iraqi officials say gunmen in Baghdad ambushed an Egyptian-owned telephone company's, Iraqna convoy on Wednesday, killing at least six security guards.
Officials said two African employees traveling in the convoy are missing and feared kidnapped.
In the southern city of Basra, U.S. officials said a roadside bomb attack killed two American security contractors and seriously wounded a third.
Iraqi and U.S. investigators are searching for kidnapped American journalist Jill Carroll, who works for the Christian Science Monitor. On Tuesday, Carroll's family appealed for her release as her abductors issued a videotape of her in captivity. Kidnappers said they will kill her unless the U.S. military releases all of its female prisoners in Iraq within 72 hours.