Lagos (AFP) -
Nigeria's ruling party candidate, former Lagos governor Bola Tinubu, edged closer to winning the presidency on Tuesday, but opposition parties called for the weekend election results to be scrapped, alleging massive manipulation of tallies.
With President Muhammadu Buhari stepping down, many Nigerians hoped a clean vote would open the way to a leader able to tackle insecurity, ease economic malaise and manage poverty in Africa's most populous country.
The voting on Saturday was mostly peaceful but was troubled by long delays at many polling stations, while technical hitches disrupted the uploading of results to a central website, fuelling concerns over vote rigging.
All Progressives Congress (APC) candidate Tinubu faced main opposition Peoples Democratic Party (PDP) candidate Atiku Abubakar and a surprise third challenger, the Labour Party's Peter Obi, whose campaign with a message of change attracted younger voters.
With official results in from 32 of Nigeria's 36 states, including the capital Abuja, Tinubu was ahead with 8.1 million votes against PDP's Abubakar, at 6.4 million votes, and Obi with 4.8 million ballots.
Tinubu, 70, is a long-time political kingmaker, who ran on his record as Lagos state governor from 1999 to 2007. But during campaigning he faced questions over his health, past graft accusations, and ties to Buhari's legacy.
-'Irretrievably compromised' -
The winning candidate has to garner the most votes nationally, but also score at least 25 percent in two-thirds of the states -- a measure reflecting a country split between a mostly Muslim north and widely Christian south, as well as three main ethnic groups.
PDP and Labour on Monday called for the vote to be scrapped, and demanded a fresh election because of what they claimed was huge manipulation of votes.
'The election is irretrievably compromised,' Labour Party chairman Julius Abure told reporters. 'We demand that this sham of an election should be immediately cancelled.'
He also called for the dismissal of Mahmood Yakubu, who chairs Nigeria's election overseer, the Independent National Electoral Commission (INEC).
'Contrary to the insinuation by both parties, results emanating from the States point to a free, fair and credible process,' the INEC said in response.
It said parties should allow the process to run its course and then take their claims to court.
One surprise result was Obi's victory in Lagos, the state with the largest number of registered voters and the traditional bastion of APC's Tinubu, known as the 'Godfather of Lagos'.
- Beset with problems -
Whoever replaces Buhari must quickly get to grips with Africa's largest economy and top oil producer, which is beset by problems including a grinding jihadist war in the northeast and double-digit inflation.
Buhari, a former army general first elected in 2015, will step down after two terms in office. His critics say he failed in his key promises to make Nigeria safer.
Nearly 90 million Nigerians were eligible to vote, with almost 10 million new voters, many under the age of 34.
INEC introduced biometric voter identification technology for the first time at national level and the IReV central database for results to improve transparency.
Votes were tallied by hand at local polling stations, with images of result sheets uploaded online to INEC's IReV.
But opposition parties said failures in the system to upload results allowed for ballot manipulation and disparities in the results from the tallies at local polling stations.
Long delays in voting and slow results frustrated many voters.
'We should have gotten the result,' said Ikechukwu Nwakile, 29, in southeast Anambra State. 'But now you can see, today is Tuesday. We have not gotten the final result which sums up that the election was not free and fair.'
Nigeria has a long history of vote-rigging and ballot buying, although INEC had said the new technology would help curtail malpractice for Saturday's presidential election.
The ruling APC party dismissed the opposition claims as an effort to 'truncate' democracy because PDP and Labour knew they were losing.
But international observers, including from the European Union, have noted major logistical problems, disenfranchised voters and a lack of transparency by INEC.
Local observer group Yiaga said it conducted a parallel vote tabulation for the presidential election and would hold a press conference after official results were released.
'If the official results are manipulated at any point in the process we will be able to expose it,' Yiaga said.
In 2019, INEC was forced to delay the election by a week just hours before voting started. PDP's Abubakar cried fraud when Buhari beat him, but the supreme court later tossed out his claim.