Burial sites found in Tikrit believed to be of cadets who were abducted from army base before executed last year.
A video purporting to show Shia militias carrying out an atrocity in Anbar province has gone viral on social media in Iraq.
The footage purports to show men belonging to the pro-government Imam Ali Brigades, burning a man they accused of being a member of the Islamic State of Iraq and the Levant (ISIL) group, over a fire.
At least one of the armed men was wearing a uniform with the badge of the Popular Mobilisation Front, a coalition of pro-government militias formed after ISIL advances last year.
The video, which was purportedly shot near the town of al-Karma, around 60km west of Baghdad, shows the men making jokes and taunting the burning body.
One militia member is heard saying the dead man, who appeared to be wearing civilian clothing, was a member of ISIL.
“We’re going to turn them into flour, grind them up,” said one fighter.
“These are the ISIL fighters, watch what happens to them,” said another masked man.
It was not clear if the man being burnt was alive when he was set alight.
History of accusations
Iraq’s pro-government militias have been accused of a number of human rights violations during their campaign to recapture territory seized by ISIL.
In March, a graphic image that went viral on Arab websites, purported to show a Shia militia member beheading a Sunni shepherd in Iraq.
In the same month after Iraqi forces captured large parts of Salahuddin province from ISIL, a video emerged showing a Sunni civilian being hit on the head with an axe, with militiamen shouting Shia religious slogans and praising victims of earlier ISIL massacres.
“This is for the heroic martyrs we lost in Camp Speicher,” one of the men is heard saying, referring to the ISIL massacre of hundreds of fleeing Iraqi soldiers at a military base near Tikrit in June 2014.
Rights group Human Rights Watch has called on the Iraqi government to do more to protect civilians from revenge attacks by the militias.
“The warring parties throughout Iraq need to protect civilians caught in the fighting and not commit looting or revenge killings,” said Joe Stork, the group’s deputy Middle East and North Africa director.
The Popular Mobilisation Force was formed after a call to arms by Iraq’s most senior Shia religious leader, Ayatollah Ali al-Sistani, and is answerable to the Iraqi government.
Sistani has condemned abuses committed by the militias.