Some bishops have emphasized the ethno-religious nature of the attacks, claiming that the largely-Muslim Fulani militants specifically target Christian villages and churches.
However, one Nigerian priest involved in conflict management recently told Aid to the Church in Need that the violence "is more of a resource conflict than a religious one," as the nomadic herdsmen are in search of water and grazing land because of desertification.
U.S. religious freedom ambassador Sam Brownback said on Thursday that violence "often plays out along faith lines" even if the conflicts were not religious in origin.
Non-governmental organizations have warned of "increasingly religious undertones" to the conflict in the last year, he said, with reports of religious sites burned and forced conversions of some kidnapping victims.
Bishop Avenya charged the Nigerian government for failing to protect Christians in the Middle Belt.
"How can one explain a scenario where as many as a hundred innocent and defenceless villagers are killed in one single attack and no one says anything about it?" he asked.
"It appears that the system has not only permitted but is also aiding the enthronement of supremacist views of one religious group against the others," he said.
Destro said that religious and political leaders and aid groups have emphasized the lack of security in the country.
"If a community calls the Nigerian equivalent of 911, nobody answers. There is no effective police protection," he said. Local communities do not have the resources to protect themselves and prosecute the perpetrators of violence.
Destro noted that "the Nigerians themselves are beside themselves" over the violence, and that "[t]here is some denial that there's religious violence, but I did not find that to be the case in most instances."
The hearing came after two more attacks on civilians were reported in international media this week. On Dec. 15, the Islamist terror group Boko Haram admitted culpability for the kidnapping of hundreds of schoolboys at a school in northwestern state of Katsina, and in the country's southeast a Nigerian priest was kidnapped by four armed men on Monday, and later released on Wednesday.
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Due to the ongoing violence against civilians in Nigeria, the State Department last week designated Nigeria a "country of particular concern (CPC)" for the first time ever-a listing reserved for the countries with the worst records on religious freedom, such as China, North Korea, and Saudi Arabia.
The CPC designation is "hopefully a true wakeup call" to the government, Smith said, noting that if there is no proper response to the designation, the U.S. should consider using sanctions.