"Local residents from Um al-Abeed region in Salman Pak told the police that they found a number of beheaded bodies on the banks of the Tigris River," the source told the independent news agency Voices of Iraq (VOI).
"Police forces rushed to the scene and found 20 beheaded corpses left on the banks of the Tigris River, south of Baghdad," he added.
Fierce clashes have been under way in the Salman Pak area for several days between security forces and gunmen.
"The unidentified bodies, all men in civilian clothes, had their hands and legs bound, and some of the heads were found next to the bodies," the source also said.
"The forces sealed off the area as a number of senior police officers arrived at the scene with U.S. troops, which started the investigation into the incident," he noted.
