Tikrit , Iraq ( CNN ) Mass graves believed to hold Iraqi soldiers have been discovered in newly liberated Tikrit . Up to 1,700 bodies may be recovered . ISIS claimed to have executed that many soldiers captured in June outside Camp Speicher , a fortified Iraqi base near Tikrit . A total of 47 bodies have been exhumed from two of the 11 mass graves discovered in Tikrit , an Iraqi government official said Tuesday . Hundreds are believed to have been executed by ISIS in June 2014 . Grieving Iraqis , apparently not related to the soldiers , gathered to pray over the bodies . When the first three bodies were found , 10 Iraqi soldiers saluted the dead by firing seven shots into the air . The national anthem was played while soldiers wept . All the bodies were decomposed . Some had their hands bound , Damon said . The remains will be sent back to Baghdad for DNA tests to establish identify , said Ali Tahir , a director in the Iraqi morgue who was supervising the digging and extraction . Damon said there may be eight mass graves inside the presidential palace complex , which contains the residences of former Iraqi President Saddam Hussein , and two other sites outside the city . The presidential palaces complex became ISIS headquarters after the militants occupied the city . Iraqi soldiers and Shiite militias retook Tikrit a few days ago after a fierce battle . Damon interviewed a soldier who said he survived the massacre by playing dead . The solider said ISIS captured the troops outside Camp Speicher and marched them to the presidential palace complex , telling them they would be safe until a prisoner swap was arranged . Once inside the compound , the soldiers were separated into smaller groups , executed and buried in mass graves , the survivor told Damon . He said he was tossed into a river and floated to an embankment . On Monday , Prime Minister Haider al-Abadi said revenge is not the way to deal with the discovery of the bodies . He said several people involved in the killings have been detained . Families of the missing soldiers had been demanding answers from the Iraqi government about what happened . As ISIS swept through northern Iraq in June , some military units were ordered to Camp Speicher . Their families claim the men received orders from their commanders to leave the base and move closer to Baghdad . They left unarmed and in civilian clothes , they say . Military commanders and the Iraqi Defense Ministry denied any such orders being issued and said the men deserted . ISIS released videos that showed what seemed to be an endless line of military recruits marched at gunpoint and later posted images showing cold-blooded mass killings . Damon said Iraqi officials told her it may take weeks or months to exhume all the bodies . Human Rights Watch described the `` Speicher Massacre '' -- as it has been dubbed in Iraq -- as the `` largest reported incident '' where `` ISIS captured more than 1,000 soldiers fleeing Camp Speicher ... then summarily executed at least 800 of them . '' Based on satellite imagery and witness testimony , Human Rights Watch last year was able to identity a number of mass grave sites inside Tikrit and the presidential palace complex . The families gave DNA samples to the Iraqi Ministry of Health last year so authorities would be able to match them to unidentified bodies the government may find . CNN 's Arwa Damon reported from Tikrit , and Ralph Ellis wrote in Atlanta . CNN 's Jomana Karadsheh contributed to this report .
A total of 47 bodies have been exhumed from two mass graves . Iraqiss find mass graves inside presidential palace compound in Tikrit . ISIS claimed to have executed 1,700 Iraqis soldiers captured outside Camp Speicher .