BAGHDAD -- Iraqi officials have begun exhuming bodies from a series of mass graves containing some of the nearly 1,700 Iraqi air force cadets believed to have been massacred by the Islamic State extremist group in June.
"We don't know how many graves there are yet," Kamil Amin, the spokesman for the Iraqi Human Rights Ministry, said Tuesday. "We're expecting big numbers."
So far, he said, officials had found 11 mass graves, each containing dozens of bodies, all located in the sprawling complex of palaces in Tikrit, north of Baghdad.
So far, 57 bodies have been identified, Amin said, adding that officials were still matching remains against a DNA database of the 1,686 cadets who were registered as missing from Camp Speicher, a former U.S. air base outside Tikrit that is now used as an Iraqi base.
When the Islamic State overran Tikrit in June, officials at the air force academy at Camp Speicher ordered 1,700 cadets to return to their homes. They left, unarmed, and fell into the hands of Islamic State fighters, officials later said. Camp Speicher itself never fell to the extremists.
The Islamic State posted videos showing groups of hundreds of the cadets being executed and boasted of having killed 1,700 in all.
Amin said officials were still searching for other mass graves in the area because the 11 mass graves identified so far were unlikely to account for all of those missing.
Many of the victims were simply thrown into the Tigris River, where 35 bodies of cadets washed up at the nearest dam downstream, in Samarra.
"We expect the river itself to be the biggest mass grave," Amin said. "And we expect that in every city of our area that is liberated we will find a mass grave full of those who opposed ISIS."
The Islamic State is sometimes referred to as ISIS.
In the northern city of Mosul on Tuesday, residents reported that the Islamic State had opened an office in the nearby village of Athiba to provide family members with the names of 300 people it had executed from villages south of Mosul. The families still were not able to find the victims' bodies, officials said.
Elsewhere on Tuesday, members of the Yazidi religious minority group complained that Kurdish officials in far northern Iraq had wrongfully arrested their top military leader, Haider Qasim Sheshu, because he would not submit to the authority of the Kurdish peshmerga forces in the area.
Sheshu is head of the Sinjar Protection Forces, and he commands a group of armed Yazidi fighters protecting refugees on top of Sinjar Mountain.
The refugees are members of the small Yazidi religious minority group that fled attacks by the Islamic State, which considers the Yazidis to be apostates. The extremists had enslaved many Yazidi women, forcing them to convert to Islam and marry Islamic State fighters.
"The peshmerga want to exploit our case and take supplies from the international community that are intended for us," said a Yazidi spokesman, Ibrahim Hodeida. "They are threatening us not to say anything and either just shut up or leave Sinjar."
A spokesman for the Kurdish Regional Government, Umeed Sabah, said at a news conference Tuesday that Sheshu was arrested because he refused to disband his fighters on Sinjar and join with peshmerga fighters instead.
"We announce that we will not allow any person to form illegal forces that are not under control of the peshmerga and will punish anyone who ignores such instructions," Sabah said.
Although Sinjar is not in the semi-autonomous Kurdistan region, Kurdish forces have led the fight against the Islamic State in that area.
Information for this article was contributed by staff members of The New York Times.
A Section on 04/08/2015