Dhaka: Iraqi extremists killed at least 160 captives in a major execution in the city of Tikrit earlier this month.
Number of dead bodies, though, could be much higher since a full investigation could not be done due to difficulty in locating bodies, said Human Rights Watch group.
Peter Bouckaert, emergencies director at the US based rights group said in a statement that the photos on the militant website and satellite images provide a clear evidence of gruesome violence which requires complete investigation.
According to The Independent, Powerful Shia cleric Moqtadaal-Sadr pledged to destroy the ground under Sunni militants, which can inflict further unrest in the region.
Sadr`s statement reportedly came out as security forces tried to repel violence in adversely affected towns.