Buhari's party claims victory in Nigeria poll
Story highlights Muhammadu Buhari's party says incumbent President Goodluck Jonathan has conceded Buhari is a 72-year-old retired major general who ruled in Nigeria in the 1980s Jonathan has been in power since 2010
All Progressives Congress party spokesman Garba Shehu confirmed Jonathan had made the call.
The Independent National Electoral Commission is still announcing the final tally in the polls, but early numbers indicate Buhari, now the President-elect, has an overwhelming majority of votes.
Buhari ruled Nigeria from late 1983 until August 1985 after ousting his predecessor in a coup.
His 20-month rule was known for what he described as a "war on indiscipline," a tough regime that some say was marred by human rights abuses.
The 72-year-old retired major general's experience as a military ruler has variably been viewed as a plus or minus in present-day Nigeria, where the government has been locked in a deadly battle with the militant group Boko Haram.
His campaign has focused on security and ending corruption in Nigeria.
Read more: Who is Nigeria's Muhammadu Buhari?
Violent protests after Nigeria's presidential elections Saturday sparked calls for calm from the two main candidates and a warning by the United States and Britain against political interference.
Demonstrators fired gunshots and torched a local electoral office in Nigeria's oil-rich Rivers state on Sunday as they marched to protest the elections amid claims of vote-rigging and voter intimidation.