A 10-year-old boy has died after a rocket was fired at a school in the Nigerian city of Jos but missed and hit a nearby building, officials say.
The school authorities say the boy was not a pupil at the large co-educational institution owned by the city's Muslim community.
The BBC's Ishaq Khalid in Jos says the students were sitting their exams at the time of the blast.
Jos has witnessed years of inter-ethnic and religious violence.
Our reporter says it is not the first time that the Nurul Islam junior and senior school has experienced trouble.
Several weeks ago some people were arrested and a bomb defused in the area surrounding the school, he says.
Jos is the capital of Plateau state, which lies on the fault line between Nigeria's mainly Muslim north and Christian and animist south.
The militant Islamist group Boko Haram, which is fighting to overthrow the government and create an Islamic state, has also been behind various attacks in the city, mainly on churches.
Last week it said it had killed two politicians who were attending a funeral for people who died during communal violence in Plateau state.