President Olusegun Obasanjo is waiting to be formally declared the runaway winner of a Nigerian presidential election marred by charges of vote-rigging.
Nigerians are hoping to end decades of instability by successfully transferring power from one elected government to another for the first time. A smooth electoral process would boost the international standing both of Nigeria and Mr Obasanjo.
But mounting allegations of election fraud, following dramatic victories by his ruling party even in opposition strongholds, have been supported by some independent poll observers and have raised fears of unrest.
With votes counted in 725 of 774 areas, Mr Obasanjo - a born-again Christian from southern Nigeria - had an unassailable lead with 21.9 million ballots, or 61.3 per cent.
His rival, Mr Muhammudu Buhari, from the predominantly Muslim north, had 11.7 million votes or 32.6 per cent. The other 18 candidates bidding to lead Africa's most populous country of 120 million shared the rest.
"We do not consider this to be an election by any stretch of the imagination," said a spokesman for Mr Buhari's All Nigeria Peoples Party (ANPP).
The ANPP has called the other 28 opposition parties to a summit in Abuja on Tuesday to discuss their next steps.Mr Buhari threatened last week to launch "mass action" if there was any rigging in Saturday's voting for president and the country's 36 state governors.
Mr Obasanjo's Peoples Democratic Party (PDP) also went on to sweep 27 of the governorships, according to latest returns.