Nigerian President Olusegun Obasanjo has declared a state of emergency in the violence-torn central state of Plateau after saying recent killings there threatened to throw the whole country into crisis.
About 1,000 people have been killed in two weeks of fighting between Christians and Muslims that began as a land dispute but evolved into a religious conflict as it spread north to Nigeria's second-largest city Kano.
The violence in central and northern Nigeria has had no impact on oil supplies from the world's seventh largest exporter, because it is hundreds of miles from the nearest oilfield.
The killing of hundreds of Muslims by Christian militia in the remote farming town of Yelwa, Plateau state, in early May sparked reprisal riots in Kano last week, where hundreds of Christians were slain by avenging Muslims. More than 70,000 people have been displaced from their homes by the fighting in the last three months.
Mr Obasanjo said the violence threatened to spill over to other states including eastern Nigeria, which fought a bloody secessionist war in the 1960s.
Mr Obasanjo said Plateau state governor Mr Joshua Dariye, whom he called "weak and incompetent" and accused of fomenting the violence, was removed from office for six months under the state of emergency.
Nigeria's population of 130 million is divided roughly equally between Muslims and Christians. "Christians and Muslims that used to live together have become arch-enemies," Mr Obasanjo said.
Under the constitution, the president can declare a state of emergency if there is a break-down of public order in any part of the country. The proclamation must be approved by both houses of the national assembly.
Mr Obasanjo's election in 1999 marked the return of Nigeria to democracy after 15 years of military rule.