Kenya's Supreme Court is to announce its decision on a challenge to the election of Uhuru Kenyatta as president.
The appeal was lodged by Kenyan Prime Minister Raila Odinga, Mr Kenyatta's rival in a presidential poll earlier this month.
Official results said Mr Kenyatta beat Mr Odinga by 50.07% to 43.28%, avoiding a run-off by just 8,100 votes.
Mr Odinga accused the electoral authorities of manipulating the result.
The presidential, legislative and municipal elections held on 4 March were the first since the disputed 2007 poll that set off ethnic and political violence in which more than 1,200 people were killed.
Mr Kenyatta and his running mate, William Ruto, are facing trial on charges of crimes against humanity at the International Criminal Court (ICC) for allegedly fuelling that unrest.
They deny the charges.
The Supreme Court can either confirm Mr Kenyatta's victory in this month's vote, or overturn the result and call for a fresh election.
The BBC's Gabriel Gatehouse reports from Nairobi that whatever the outcome, there will be people who are angry.
Outgoing President Mwai Kibaki has urged people to stay calm and accept the result, but much will depend on Kenyans' faith in their newly-reformed judiciary, our correspondent adds.
Lawyers for Mr Odinga say their petition to the Supreme Court included allegations of vote manipulation, as well as problems with the registration of voters and an electronic vote counting mechanism.
On Friday, the Supreme Court reviewed recounts from 22 polling stations. Both sides claimed that the recounts vindicated their position.
Mr Kenyatta has called the election, which was largely conducted peacefully, a "triumph of democracy".
The Independent Electoral and Boundaries Commission (IEBC) has also insisted that the vote was credible, despite technical failures with an electronic voter ID system and the vote counting mechanism.
International observers said the poll was largely free, fair and credible, and that the electoral commission had conducted its business in an open and transparent manner.
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