Ghana has been forced to extend voting in its presidential election by another day after technical glitches led to long delays in some areas in a country seeking to burnish its democratic credentials.
Voting went smoothly in many areas, but a new biometric system requiring electronic fingerprints from voters suffered a number of breakdowns in certain districts, resulting in long lines and frustration.
Materials also arrived late in some areas, causing some polling stations to open far behind schedule.
President John Dramani Mahama is vying for a first elected term against main opposition candidate Nana Akufo-Addo in a nation reaping the benefits of a booming economy fuelled in part by a new and expanding oil industry.
The results are expected to be close in a country that has been seeking to live up to its reputation as an example of stable democracy in turbulent West Africa. Voters are also electing a 275-seat parliament.
An electoral commission statement said the directive applied to polling stations where the biometric system broke down or where delivery of materials arrived especially late.
"We are talking about isolated instances," electoral commission chief Kwado Afari-Gyan told AFP. "It is not a mass problem. There will enough biometric verification machines" to handle the extended voting Saturday.
Spokesmen for the two main political parties expressed support for the commission, however voters who were still in line at some stations reacted angrily.
The announcement came even with counting already underway in districts where voting was completed.
Results from the vote had been expected as early as Sunday, but it was unclear whether that timeframe would remain after the extension.
There were a total of eight presidential candidates, which could result in a second round on December 28.
Long lines formed in many areas earlier in the day and a number of voters waited all night to be able to cast ballots in the morning.
Mahama, after voting in the country's northern region, addressed the late start in some areas, saying he had been informed "that the problems have been resolved".
"This year's elections will go down in history as the best ever to be held in Ghana," he said.
Akufo-Addo voted in the country's eastern region and expressed hope that the elections would remain peaceful.
There were rowdy crowds in some areas, but local observers said they had not received reports of any major incidents.
In the Jamestown area of the capital Accra, one of the city's oldest neighbourhoods with faded colonial architecture and congested streets, voters grew angry after waiting hours and shouted at authorities.
A polling station opened late, followed by problems with the biometric system.
Vida Armah, a 19-year-old student, said she waited more than seven hours to cast her ballot. Asked what would happen if people were not allowed to vote, she said "there will be a war".
Voters in other areas where the process had gone smoothly expressed pride in being able to cast ballots.
Comfort Baiden said she had arrived at 1:00 am to wait because she had to make it to work by 8:00 am. The seamstress said she had spent the night on a plastic chair reading a book.
"I have to vote because I'm a Ghanaian and the vote is my future," she added.
Ghana has had five elections since military rule ended in 1992, but the stakes are seen as higher than ever this time, as commercial oil production that began in 2010 is set to expand.
Mahama, 54, of the National Democratic Congress, only took power in July, when his predecessor John Atta Mills died following an illness.
The 68-year-old Akufo-Addo of the New Patriotic Party, the son of a former president, lost by less than one percentage point in 2008.
Ghana, the first sub-Saharan African nation to gain independence from colonial rule in 1957, suffered a number of military coups before returning to democracy in 1992.
Subsequent elections have seen both parties voted out of office, establishing Ghana's democratic credentials in a region that has seen its share of rigged polls and coups.
US President Barack Obama chose Ghana for his first visit to sub-Saharan Africa after taking office in 2009.
Ghana is also a top exporter of cocoa and gold, with economic growth of 14 percent in 2011. Eight percent growth is expected for 2012 and 2013.
How to spend Ghana's oil money has been a key issue. Mahama has advocated a large investment in infrastructure, while Akufo-Addo has promoted his signature policy of free secondary education.