Iraqi officials have exhumed more than 470 bodies believed to have been executed by the self-proclaimed Islamic State of Iraq and al-Sham (ISIS) near Tikrit, a province located 140 km northwest of Baghdad, last year in what is known as the Speicher Massacre, the health minister Adila Hommoud said on Thursday.Hommoud said at a press conference in Baghdad that they exhumed the bodies of 470 Speicher martyrs from burial sites in Tikrit.In June 2014, armed men belonging or allied to ISIS abducted hundreds of young, mostly Shiite recruits from Speicher military base, just outside the city of Tikrit.They were then lined up in several locations and executed one by one, as shown in pictures and footage later released by ISIS.Some were pushed into the Tigris River, others hastily buried in locations that were discovered when government and allied forces retook Tikrit from the extremists about two months ago.The highest estimate for the number of people killed in one of the worst atrocities committed by ISIS stands at 1,700.The exhumed remains came from four burial sites, including one which contained 400 bodies, said Ziad Ali Abbas, the chief doctor at Baghdad's main morgue."There were several layers of bodies all piled on top of each other," he said, adding that 50 bodies were found in a second site and nine more in the two remaining graves.He said forensic examination of the remains was conducted with foreign assistance, including from the International Committee of the Red Cross.Hundreds of families whose sons, fathers and brothers went missing at the time of the ISIS-led offensive in Iraq have been waiting for confirmation that their loved ones were among the Speicher victims.Officials at Thursday's press conference said the first list of names would be released next week, after weeks of DNA testing.Identification documents the victims were carrying at the time of their capture were also found near burial sites.The health minister said the figure of 470 was not final."The work to exhume Speicher victims continues," Hammoud said.Officials had said in mid-April that up to 10 different suspected burial sites were identified in the Tikrit area as a result of its recapture by government forces in late March and the first days of April.