The ISIS takfiri group on Saturday released new footage of its June 2014 massacre of hundreds of military recruits in Tikrit.The highest estimates put at 1,700 the number of cadets ISIS gunmen captured at the Speicher military base near Tikrit and executed at various locations, mostly in the city ' s former presidential palace complex. The 22 - minute video posted on the terrorist forums, which included both new and previously released footage, showed hundreds of executions, providing further evidence of the scope of the atrocity. Some of the victims are shown pleading for their lives, attempting to explain they had only just joined the security forces. The grisly footage showed executions on an industrial scale, with victims falling out of dump trucks and later lying side by side in shallow mass graves before being shot dead one by one.Recommended:Key ISIS leader killed in eastern Afghanistan The killing went on into the night and the video showed an excavator being used to move piles of bodies. Around 600 bodies have been exhumed since government and allied fighters retook Tikrit from ISIS in April but many of the victims were dumped into the Tigris river. Combined with a call by the country's top cleric Grand Ayatollah Sayyed Ali al-Sistani for Iraqis to take up arms against ISIS, the Speicher massacre played a key role in the mass recruitment of Iraqi volunteers to fight the terrorists.