U.N. Warns of Possible Crimes against Humanity in Nigeria

Members of Nigeria's Islamist Boko Haram could be guilty of crimes against humanity if they carried out systematic attacks on religious targets, U.N. human rights chief Navi Pillay warned Thursday.

"Members of Boko Haram and other groups and entities, if judged to have committed widespread or systematic attacks against a civilian population -- including on grounds such as religion or ethnicity -- could be found guilty of crimes against humanity," said a statement from Pillay.

Any "deliberate acts leading to population cleansing on grounds of religion or ethnicity would also amount to a crime against humanity," added the U.N. High Commissioner for Human Rights.

Recent religious violence, most of it blamed on Boko Haram, has sparked fears of a wider religious conflict and even civil war in a country roughly divided between a mainly Muslim north and predominantly Christian south.

Pillay stressed that there "must be no impunity for any acts of violence, including those committed in retaliation for earlier attacks."

She also urged the government to speak out against the violence, saying that Nigerian leaders must "avoid falling into the trap of calling for, or sanctioning, retaliation or making other provocative statements.

"It is essential that the country's leadership, and especially its Muslim and Christian leaders, join forces to unequivocally condemn all violence, including retaliation, and encourage their followers to identify and help arrest all those involved in killings and other acts of violence that have been taking place," she added.