Nigerian President Olusegun Obasanjo assumed emergency powers to govern the violence-torn central state of Plateau on Tuesday, saying recent killings there threatened to plunge the whole country into crisis.
About 1,000 people have been killed in two weeks of fighting between Christians and Muslims which began as a land dispute in Plateau, but turned into a religious conflict as it spread north to Nigeria's second largest city Kano.
Obasanjo said he had suspended Plateau state governor Joshua Dariye for six months and had also suspended the state assembly. He said Dariye was "weak and incompetent" and accused him of fomenting the violence.
He appointed retired general Chris Alli, chief of army staff under the late dictator Sani Abacha, as interim administrator of the state.
"I hereby declare a state of emergency in Plateau state," Obasanjo said in a national televised address. "If allowed, the crisis will engulf the entire nation."
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 oilfields in the south.
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 in which Muslims slew hundreds of Christians.
More than 70,000 people have been displaced from their homes by the fighting in the last three months.
Obasanjo said the violence threatened to spill over to other states including eastern Nigeria, which fought a bloody secessionist war in the 1960s.
Nigeria's population of 130 million is divided about equally between Muslims and Christians.
"Christians and Muslims that used to live together have become arch-enemies," Obasanjo said.
Under the constitution, the president can declare a state of emergency if there is a breakdown of public order in any part of the country. The proclamation must be approved by a two-thirds majority of the national assembly.