"Iraqi insurgents executed at least 160 captives earlier this month in the northern city of Tikrit, Human Rights Watch said Friday, citing an analysis of satellite imagery and grisly photos released by the militants. The U.S.-based rights group said militants from the Islamic State of Iraq and the Levant 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...Chief Iraqi military spokesman Lt. Gen. Qassim al-Moussawi 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 in areas held by the Islamic State. He told The Associated Press at the time that an examination of the images by military experts showed that about 170 soldiers were shot to death after their capture. Captions on the photos showing the soldiers after they were shot say 'hundreds have been liquidated,' but the total could not be verified. The massacre appeared to be aimed at instilling fear in Iraq's demoralized armed forces -- which melted away as militants seized much of the north in a matter of days -- as well as the country's Shiite majority, whom the Islamic State views as apostates. 'This is the fate that awaits the Shiites sent by Nouri to fight the Sunnis,' one caption read, apparently referring to Prime Minister Nouri al-Maliki."