Baghdad: Iraqi insurgents executed at least 160 captives earlier this month in the northern city of Tikrit, Human Rights Watch said on Friday, citing an analysis of satellite imagery and grisly photos released by the militants.

The US-based rights group said militants from the Islamic State of Iraq and the Levant (Isil) killed between 160 and 190 men in two locations in Tikrit between June 11 and June 14. “The number of victims may well be much higher, but the difficulty of locating bodies and accessing the area has prevented a full investigation,” it said.

After overrunning large swaths of northern Iraq and capturing the cities of Mosul and Tikrit earlier this month, the Islamic extremist group posted graphic photos on a militant website that appeared to show fighters loading dozens of captured soldiers onto flatbed trucks before forcing them to lie in a shallow ditch with their hands tied behind their backs. A final set of photos shows bodies.

“The photos and satellite images from Tikrit provide strong evidence of a horrible war crime that needs further investigation,” Peter Bouckaert, emergencies director at Human Rights Watch, said in a statement.

Chief Iraqi military spokesman Lt Gen Qasim Al Mousawi confirmed the photos’ authenticity on June 15, after they first surfaced, and said he was aware of cases of mass murder of captured Iraqi soldiers.