At least 16 bodies of people apparently killed execution-style have been found in a Sunni Muslim insurgent stronghold, Qaim in western Iraq.
Witnesses say many of the bodies were blindfolded, bound and clad in civilian clothes.
It was unclear if the bodies were related to some 20 Iraqi soldiers that disappeared from the area Tuesday.
Separately, Iraqi authorities say gunmen shot dead two senior police officials in Kirkuk and another two police officers in Basra.
The U.S. army said Friday it is launching a criminal investigation into the killing of two army officers at a base north of Baghdad on Tuesday. Officials first reported they had been killed by mortar fire, but say a later investigation ruled that out.
Some information for this report provided by AP and Reuters.