In video footage of what is described as the edge of Maiduguri city in northern Ni­ger­ia, more than 10 young men are seen sitting in line next to a freshly dug pit. One by one, some are brought to the edge; their throats are cut, and their bodies are rolled in.

The perpetrators are not part of the militant Islamist group Boko Haram, according to testimony gathered by Amnesty International, which obtained the footage, but are alleged to be members of the Ni­ger­ian military.

At the end of the U.S.-Africa leaders summit Wednesday, President Obama emphasized the need “to build strong, professional security forces” on the continent. Ni­ger­ian President Goodluck Jonathan spoke at the summit about the need for more effective global action to counter terrorism. But as the Ni­ger­ian government steps up its campaign against Boko Haram, which recently drew global attention for the kidnapping of more than 200 girls, there are growing reports of extrajudicial killings and arbitrary arrests by government forces.

“The actions of the Nigerian military have had just as devastating an impact on the human rights of the Nigerian people as Boko Haram’s,” said Steven W. Hawkins, executive director of Amnesty International USA.

Ni­ger­ian officials reject Amnesty’s allegations and questioned the authenticity of the video.

“There are no extrajudicial killings in Nigeria,” said the Nigerian ambassador to the United States, Adebowale Ibidapo Adefuye, in a brief phone call Thursday. “I have not heard about that video”

But the Nigerian military is studying the video footage “with a view to identifying those behind such acts,” said Defense Headquarters spokesman Chris Olukolade, according to the Associated Press.

Last month, Jonathan asked the Ni­ger­ian legislature for approval to borrow $1 billion to aid the government’s fight against Boko Haram, in addition to about $6 billion that already has been allocated to the country’s security budget this year.

The Boko Haram insurgency in Nigeria’s predominantly Muslim north has been escalating for five years, but it drew international attention with the kidnapping of the schoolgirls from the northeastern village of Chibok in March.

An estimated 4,000 people have been killed this year alone, according to Amnesty, and in the past few weeks, a spate of bombings has rocked the north.

In a bilateral meeting between Jonathan and Vice President Biden on Tuesday, Biden said the United States was committed to working with Nigeria to defeat Boko Haram, but he also stressed the need to protect human rights and improve socioeconomic and security conditions in the north.

Shehu Sani, a prominent human rights activist in Kaduna, which is considered the political capital of northern Nigeria, said atrocities by the military will deepen the conflict.

“The situation clearly shows that the government has been adopting a cruel and bloody approach to crush the insurgency; it has been aiding, abetting and supporting gross rights violations,” he said in a telephone interview Wednesday from Kaduna. “What we should not forget is that this indiscriminate use of force was the basis for the beginning of the insurgency.”

Dina, a lawyer from Maiduguri who asked that her last name be withheld for personal security reasons, said the military’s use of curfews and checkpoints as well as the routine harassment of young men has frustrated people who initially supported a greater troop presence in the north. She said her two brothers had been killed by suspected Boko Haram militants but the government response to the group has been troubling and indiscriminate.

“The military were harassing civilians, bursting into houses, making all sorts of wild accusations,” she said in a telephone interview from Texas, where she is visiting with her husband. “If they saw young boys talking on the street, they would immediately see them as suspects and detain them.”

She said what the region needs is investment in education and jobs.

Horace Campbell, a professor of political science and African American studies at Syracuse University, said the summit was an important indication that the United States wants to reengage with Africa, but if it is to be successful it cannot focus exclusively on threats — viewing the continent as a hotbed of disease, war and now Islamic extremism.

“The U.S. does not have a security policy toward Africa,” said Campbell. “That is to say, it does not have a policy to secure African lives.”

The key to combatting Boko Haram, he said, is social — mobilizing and supporting communities in the region and engaging traditional leaders, Muslim clerics, women, youth and local media.

“We should not in any way allow Boko Haram to be used as an excuse to militarize northern Nigeria,” Campbell said.