The victim, identified as Deborah Samuel, was stoned to death and beaten to death at Shehu Shagari College of Education in Sokoto on Friday, police said.
Authorities closed the school and told other students to evacuate. Nonetheless, students on Saturday rallied to demand the release of two of their fellow students detained by police on suspicion of involvement in the killings.
Samuel, the murder of a Christian, highlights the deep divisions along religious lines in Africa’s most populous country, where violence has erupted in response to actions or comments previously considered anti-Islamic.
In the remote state of Kaduna, about 500 kilometers (310 miles) from Sokoto, the state government also banned protests “related to religious activities,” citing “steps by some patriotic elements” to organize a protest over the incident in Sokoto.
Christian and Muslim leaders have similarly condemned the student killings and called for the perpetrators to be brought to justice.
Nigerian President Muhammadu Buhari said “the news of the killing of a young girl by fellow students is a matter of concern and calls for an impartial, comprehensive investigation into what happened before and during the incident,” a spokesman said in a statement.