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Forcing detainees to dig their own graves, slitting prisoners' throats in gruesome ceremonial killings, and conducting arbitrary mass executions. These are not charges leveled against Nigeria's brutal Islamist group Boko Haram, but the alleged human rights abuses of government troops tasked with fighting them, according to a report published Monday.

The atrocities of the al-Qaeda-linked sect Boko Haram have been well documented since the kidnap of more than 200 girls in April sparked the international #BringBackOurGirls campaign.

But a report released Monday by human rights group Amnesty International has provided some of the most in-depth coverage yet of the alleged abuses committed by Nigerian security forces tasked with battling Boko Haram and protecting the country's civilians.

One grisly incident tells of two young men forced to dig their own graves by apparent members of the government-backed Civilian Joint Task Force (CJTF).

One of the detainees is held down while the leader of the group raises a knife, kisses it and shouts: "Die hard, commando," before slitting the prisoner’s throat, according to a video gathered by Amnesty, which verified the footage with two Nigerian security sources. Other members of the CJTF group are heard shouting: "Yes oga (boss), kill him."

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"War crimes are being committed with abandon by all sides in the conflict"

Several of the armed captors wore military uniforms bearing the name "Borno State Operation Flush," a local state-backed militia, according to Amnesty. NBC News reached out to Borno Senator Ahmed Zanna but he was unavailable for comment.

The incident took place in Maiduguri, the capital of the Nigeria's northeastern Borno state that has become a stronghold for Boko Haram. The group’s name roughly translates to "western education is a sin" and its aim is to destroy Nigeria's oil-driven economy and set up an Islamic state. The government of Nigeria is ranked as one of the most corrupt countries in the world, according to Transparency International.

Borno state, in Nigeria’s Muslim-majority north, has seen more than half of the 22,000 conflict-related deaths in Nigeria since May 2011, according figures from to the New York-based Council for Foreign Relations (CFR).

The video was shot on March 14, the same day as the alleged extrajudicial execution of some 600 prisoners at the town’s Giwa Barracks in the chaotic aftermath of a Boko Haram raid to free fighters held there.

Our prayers are with the missing Nigerian girls and their families. It's time to #BringBackOurGirls. -mo pic.twitter.com/glDKDotJRt -The First Lady (@FLOTUS) May 7, 2014

NBC News sent a copy of Amnesty's report before its publication to Boko Haram expert John Campbell, a Senior Fellow for Africa Policy Studies at the CFR. He said the claims were "all very credible, I'm afraid - with a chilling specificity."

According to Campbell, Nigeria's security forces are responsible for killing just as many civilians as Boko Haram.

"Boko Haram is an extremely violent group and since 2009 has basically killed any soldier or policeman it has gotten its hands on," Campbell said. "Whenever you have got this level of violence and brutality it quickly spirals on both sides."

Amnesty’s report also details a terrifying "screening" operation in the town of Bama, 40 miles south-east of Maiduguri, on July 23. Residents told Amnesty that scores of Nigerian military and CJTF personnel told all adult males to gather in the central market at 11 a.m. and remove their clothes.

The men were then lined up one by one, told to close their eyes, and pushed in front of one of the CJTF personnel who told them to go "left" or "right." The 35 men who were sent left were deemed alleged Boko Haram members and beaten with clubs and machetes and later executed, according to eyewitnesses. The 300 who were told to go right were deemed innocent.

"This shocking new evidence is further proof of the appalling disregard for humanity in north-eastern Nigeria, where war crimes are being committed with abandon by all sides in the conflict,” said Salil Shetty, Amnesty International’s Secretary General. “What does it say about a country when members of its military carry out such unspeakable acts and then deliberately capture the images on film?"