ABUJA Below are answers to some questions on Nigeria's elections after President Goodluck Jonathan secured victory over closest rival Muhammadu Buhari according to a tally of official figures.
The Independent National Electoral Commission has yet to publish the full results and declare the winner.
WHAT DOES VICTORY MEAN?
Jonathan gets another four years in office as leader of Africa's most populous nation.
But Buhari's largely-Muslim north is unhappy with the results and disturbances have already begun in a region where thousands have died in bouts of ethnic unrest in past decades.
Because Jonathan is the first president from the oil-producing Niger Delta region, it could help ensure his volatile home region remains calm for a while.
Jonathan has promised economic reforms, including to the critical power sector, where failure to establish reliable supplies has sapped the strength of Africa's third biggest economy for decades.
HOW WELL DID THE ELECTIONS GO?
Much better than those in the past, although that wasn't hard in a country where ballot box stuffing, thuggery and simply making up results has been the norm.
Local and foreign observers hailed this vote and the parliamentary election a week earlier as the fairest in decades, although Buhari's supporters believe many results were fixed.
Results showed the stark polarisation between the north and the more heavily Christian south once many Nigerians had a genuine chance to make their allegiances clear.
The elections are not over yet either.
Polls for state governors are due on April 26 and while they will get less international scrutiny, there is a far greater chance of violence and rigging for lucrative posts leading 36 states that are larger than many African countries.
Stakes are high in state elections, closer to home for many Nigerians than the relatively remote presidency.
WHAT DOES IT ALL MEAN FOR OIL PRODUCTION?
A win for Jonathan as president should avert any short-term resumption of unrest in his home region. Disturbances by groups demanding a greater share of the region's wealth shut in as much as a quarter of production in recent years.
In the longer term, there remains a danger of a return to unrest if Jonathan does not deliver on very high expectations. State elections could also be a cause for concern at a localised level.
Because oil production that had been shut in by unrest had generally been brought back onstream, there is little immediate prospect of upside to output as a result of a smooth election.
WHAT WILL IT MEAN FOR MARKETS?
Nigerian markets have been treading water.
A market rally could follow a process which ended without a potentially divisive run-off vote and was greeted by observers as the most credible Nigerian election for decades. But possible post-election disturbances could still cause jitters.
While democratic systems are generally welcomed in Africa for bringing greater oversight and transparency, specific election cycles are always a concern because of the risks of trouble as well as government overspending.
WILL EVERYONE ACCEPT THE RESULTS?
That looks unlikely. Buhari's Congress for Progressive Change (CPC) has pointed to malpractice and its representatives did not sign off on voting sheets in some areas. They have said they will wait for all results before challenging them.
They believe Jonathan's People's Democratic Party (PDP) manipulated results to give him an overwhelming majority in southern parts of the country and to ensure that he got at least the minimum number of results needed across northern states to avoid a second round run-off.
HOW CAN RESULTS BE CHALLENGED?
Buhari has said he won't go to court, but his party could.
An election petition has to be filed within 21 days to the Court of Appeal. This has 180 days to give judgement in writing. Any further appeal has to be disposed of within 90 days.
Given the apparent margin of Jonathan's victory, chances of success may be limited even if problems are found in some areas.
The broad stamp of approval given to the election by observers will not strengthen the case for any appeal.
WHAT ABOUT PROTESTS? Unrest is already brewing in northern Nigeria, where opposition supporters feel they have been cheated.
This could stoke bloody ethnic and religious disturbances targeting Nigerians from other parts of the country who live in the north. That could then trigger reprisals elsewhere.
A North Africa style uprising across Nigeria is unlikely.
Most parts of Nigeria appear to broadly support Jonathan and would be highly unlikely to rally behind a northern grievance.
That could confine protests to the already relatively marginalised north, furthest from the oil industry or other major economic activity. The risk for protesters is that it is their own part of Nigeria which suffers the most.
(Editing by Nick Tattersall)