By MacDonald Dzirutwe and Sofia Christensen
LAGOS (Reuters) - Nigerians were voting in presidential and parliamentary elections on Saturday that are seen as the most wide open since the country switched from military rule to democracy in 1999.
Of the 18 candidates vying to succeed President MuhammaduBuhari, three stand a chance: former Lagos Governor Bola Tinubu,70, the ruling party candidate; former Vice President AtikuAbubakar, 76, the main opposition candidate; Peter Obi, 61, achallenger popular among young voters.
The following explains the election logistics:
WHEN IS IT?
Voting takes place from 8.30 a.m. to 2.30 p.m. (0730 GMT to 1330 GMT) on Feb. 25. Voters who join a polling station queue on time will be allowed to cast their ballots after closing time.
WHEN WILL RESULTS BE ANNOUNCED?
The counting and collating process is expected to take several days. While INEC has not said exactly when it would declare official results, this is expected to take place in the first half of next week.
HOW BIG IS IT?
More than 93 million people are registered to vote. There will be about 176,600 polling stations across thecountry, including in camps for people displaced by conflictbetween Islamist insurgents and federal troops in the northeast.
WILL IT BE CLEAN?
The Independent National Electoral Commission (INEC) says ithas taken measures to ensure this election will be free and fair- a major concern in a nation with a long history of electoralfraud and violence.
Voters will present their voting cards and be identified bya Bimodal Voter Accreditation System (BVAS) that usesfingerprints and facial recognition. This is aimed at reducingthe risk of fraudsters voting several times.
On voting day, results from individual polling stations willbe pasted outside for citizens to view, and sent through BVAS toan INEC portal. The results will be displayed on the portal inreal time and accessible by the public, INEC says.
It is hoped this will reduce the risk of the figures beingmanipulated along the way.
INEC says that citizens wishing to witness the sorting andcounting of ballot papers at polling stations should do so froma distance of 300 metres (yards). In the past, one of the forms of vote-rigging seen in Nigeria was the intimidation of electoral officials by thugs paid by politicians.
WHAT DO CANDIDATES NEED TO WIN?
A presidential candidate must receive the largest number ofvotes cast nationwide and at least a quarter of the vote in nofewer than 24 of the country's 36 states.
If no one clears both hurdles, the top two candidates willcompete in a run-off. The constitution says the run-off musttake place within 21 days of the announcement of the result.
No run-off has been necessary since the transition todemocracy.
For the parliamentary poll, candidates for a seat in theHouse of Representatives or the Senate must win a simplemajority of votes in the constituency or senatorial districtthey are contesting in order to win.
(Editing by Estelle Shirbon and Alex Richardson)