Fighters from the Islamic State in Iraq and the Levant (ISIL) have executed at least 160 captives this month in Iraq's northern city of Tikrit, according to Human Rights Watch (HRW).
The U.S.-based rights group says fighters from the Al-Qaeda splinter group killed between 160 and 190 men in two locations in Tikrit over just three days after they overran the city on June 11.
It said the number of victims could be "much higher," but the difficulty of locating bodies and accessing the area has prevented a full investigation.
ISIL claimed to have executed 1,700 Shi'ite members of the Iraqi Army in Tikrit and posted graphic photos of apparently executed men on a militant website.
ISIL, and their Sunni allies, have overrun large parts of northern and western Iraq.
Based on reporting by AP and dpa