(CNN) Forced cannibalism, gang rapes and death by burning are among the atrocities marking the brutal civil war taking place in South Sudan, according to an African Union (AU) report.

South Sudan seceded from Sudan in 2011 after decades of war, making it the world's youngest nation. But it has been embroiled in conflict since December 2013, when President Salva Kiir accused his fired deputy, Riek Machar, of trying to oust him through a coup.

Since then, militias loyal to both men have battled against each other. The nation divided along tribal lines -- the Nuer community backs rebel leader Machar, while the President is from the Dinka tribe.

The United Nations estimates more than 2.2 million people have been displaced and South Sudan has faced food shortages and disease in conjunction with the violence.

The AU's Peace and Security Council mandated a commission of inquiry in December 2013 to investigate human rights abuses and other abuses in the conflict.

The commission began work in March 2014, talking to witnesses and officials and visiting scenes of alleged crimes. Its report was released Tuesday.

'I have seen people being forced to eat other humans'

JUST WATCHED South Sudan faces worsening food crisis Replay More Videos ... MUST WATCH South Sudan faces worsening food crisis 02:15

"The stories and reports of the human toll of the violence and brutality have been heart-wrenching: reports of people being burnt in places of worship and hospitals, mass burials, women of all ages raped; both elderly and young, women described how they were brutally gang raped, and left unconscious and bleeding, people were not simply shot, they were subjected, for instance, to beatings before being compelled to jump into a lit fire," the report said.

"The Commission found cases of sexual and gender based violence committed by both parties against women. It also documented extreme cruelty exercised through mutilation of bodies, burning of bodies, draining human blood from people who had just been killed and forcing others from one ethnic community to drink the blood or eat burnt human flesh," it said.

Commissioner Mahmood Mamdani , in an opinion accompanying the main report, quoted an internally displaced survivor at a camp in Juba -- one of the main conflict areas -- as telling the inquiry:

"I have seen people being forced to eat other humans. Soldiers kill one of you and ask the other to eat the dead one. Women are raped, people burnt. I was a student in Nairobi, Kenya -- I am not a military."

Seeking justice

Most of the atrocities were carried out against civilians with no active role in the conflict, the commission found -- by both sides. It said the use of child soldiers was "pervasive" and had been witnessed by commissioners during their inquiry.

Photos: Child soldiers around the world Photos: Child soldiers around the world Children sit with their rifles at a ceremony taking place in South Sudan on the issue of the disarmament, demobilization and reintegration of child soldiers. The process was overseen by UNICEF and partners in February 2015. Hide Caption 1 of 15 Photos: Child soldiers around the world An armed Yemeni youth sits amid the rubble in December 2014, guarding the damaged house of the Iranian ambassador in the capital Sanaa. Hide Caption 2 of 15 Photos: Child soldiers around the world A youngster in military uniform in the South Sudan Democratic Movement/Army in Jonglei state in March 2014. Despite the dominant image of these soldiers as young boys, it is estimated that globally as many as 40% are girls. Hide Caption 3 of 15 Photos: Child soldiers around the world A young rebel fighter holds a weapon at the entrance of a house in the Syrian city of Aleppo in March 2013. Hide Caption 4 of 15 Photos: Child soldiers around the world Child soldiers from the United Wa State Army (UWSA) in the so-called southern Wa State in Myanmar. Hide Caption 5 of 15 Photos: Child soldiers around the world A young fighter from the Al-Shabaab militia shows his wounded hand after battling Somali government forces in Mogadishu in July 2009. Hide Caption 6 of 15 Photos: Child soldiers around the world A young boy fighting for the Lord's Resistance Army stands guard in South Sudan as LRA leader Joseph Kony meets with the Southern Sudan vice president in July 2006. Hide Caption 7 of 15 Photos: Child soldiers around the world A Liberian militia child loyal to the government walks away from firing on rebel forces across a key bridge while another taunts them in Monrovia in 2003. Hide Caption 8 of 15 Photos: Child soldiers around the world A child soldier is helped by another militiaman as he puts on the traditional chief's hyena skins in an undisclosed location near Bunia in the Democratic Republic of Congo in 2003. Hide Caption 9 of 15 Photos: Child soldiers around the world A Chadian child soldier stands in front of a machine gun at De Roux camp in Bangui, Central African Republic, in 2003. Hide Caption 10 of 15 Photos: Child soldiers around the world Two children enrolled with Sierra Leone troops battling rebels of the Revolutionary United Front get ready to fight east of the capital of Freetown in May 2000. Hide Caption 11 of 15 Photos: Child soldiers around the world A 12-year-old soldier in Kamerplaw, southern Myanmar, at the headquarters of God's Army, in 2001. God's Army was a breakaway guerrilla faction of the Christian Karen National Union. Hide Caption 12 of 15 Photos: Child soldiers around the world Child soldiers of the resistance Mong Tai Army during training with their commander in Myanmar in 2001. Hide Caption 13 of 15 Photos: Child soldiers around the world A child with a gun sits in a car with Rwandan Patriotic Front partisans patrolling the streets of Kigali, Rwanda, in June 1994. Hide Caption 14 of 15 Photos: Child soldiers around the world Young recruits are addressed by the head of the so-called Mong Thai Army in Burma in 1990. Hide Caption 15 of 15

South Sudan's war has continued despite several ceasefire attempts but in their report the AU commissioners looked towards future justice.

They said they had identified a list of alleged perpetrators of the atrocities and recommended that an African Union-backed legal mechanism be established to bring those with the greatest responsibility to account.

In their report, they called for the establishment of a Truth and Reconciliation Commission to investigate human rights violations back to an agreed cut-off date.

"Such a body should lead to truth, forgiveness and restitution where necessary, justice and lasting reconciliation being achieved," the report said.