Hackers have targeted the website of Ghana’s electoral commission as votes are counted after tightly contested elections.
The commission says the website is up again, but it it is currently blank.
The commission has tweeted, urging people to ignore “fake results” circulating on social media.
President John Mahama is facing a strong challenge from main opposition leader Nana Akufo-Addo in a campaign dominated by Ghana’s faltering economy.
Wednesday’s election passed off peacefully, but voting was postponed to Thursday in one constituency after voting material failed to arrive on time.
A run-off will be held later in the month if neither of the two main candidates secures more than 50% of the votes.
In the previous election in 2012, Mr Mahama defeated Mr Akufo-Addo by less than 300,000 votes.
“We deplore the attempt to hack the EC’s [electoral commission’s] website. Please respect the integrity and independence of the EC,” it said in a tweet.
All seven candidates have pledged to keep the process peaceful but an opposition supporter died when a rally tuned violent on Monday.
Results are expected in the next two days
Voting in his northern home region of Bole on Wednesday, where he was mobbed by a cheering crowd, President Mahama said Ghana’s democracy had “matured” and this election would further consolidate it.
Asked about corruption, he told AFP news agency: “There is a general perception of corruption in all African countries. I think it is a stage of our development. As we continue to strengthen the institutions of state, I think that people will come to see the integrity in these institutions.”
Mr Akufo-Addo said he hoped for an orderly election as he voted in Kibi in the south of Ghana.
“It’s very important that this process goes off efficiently and smoothly and peacefully so that Ghana continues to maintain its deserved image of being a democracy that takes democracy seriously,” he said.
The candidates signed a pact last week vowing to follow electoral rules and keep the peace.
Clashes near the border with Togo on Monday left one person dead and six in a critical condition.
Defeat for Mr Mahama of the National Democratic Congress (NDC) would make him the first incumbent to lose an election since Ghana returned to multi-party democracy.
He has been nicknamed “Mr Dumsor”, a local word that refers to the power cuts that have blighted the country during his term, but on the campaign trial has been trying to convince Ghanaians that he is delivering on his promise of creating more jobs.
Mr Akufo-Addo has promised free high-school education and more factories, but his critics have questioned the viability of his ambitions.
The other four candidates include former first lady Nana Konadu Agyeman-Rawlings of the National Democratic Party (NDP), whose husband Jerry John Rawlings initially took power in the 1979 coup.
She is the first woman to run for president in the West African country.
NDC candidate: John Dramani Mahama, 58
- Vice-president under President John Atta Mills, who died in 2012. Completed his term
- Now seeking re-election after serving his first term of four years
- Political pedigree: His father was first minister of state for the Northern region
NPP candidate: Nana Addo Dankwa Akufo-Addo, 72
- Campaigned for a return to multi-party democracy under military rule
- A former justice and foreign minister in the NPP government from 2001 to 2007, he is running for president for a third time
- Political pedigree: His father was a prominent politician who served as chief justice and ceremonial president