Kenyans are awaiting results in their country's presidential election, after millions cast their votes on Monday.
With over a third of polling stations reporting, Deputy Prime Minister Uhuru Kenyatta held an early lead over his main rival, PM Raila Odinga.
The head of the electoral commission emphasised these were provisional figures and urged Kenyans to wait patiently for the final outcome.
In 2007-8, more than 1,000 people were killed in post-election violence.
Clashes broke out after Mr Odinga claimed he had been cheated of victory by supporters of President Mwai Kibaki.
Violence has also marred the current election, with at least 19 people killed on Monday - mainly in coastal attacks attributed to separatists.
Also hanging over this vote is Mr Kenyatta's indictment to appear before the International Criminal Court (ICC) in April for his alleged role in the 2007-8 bloodshed.
Officials and the media urged Kenyans to put their faith in the electoral process.
The election was a "turning point" whose outcome would determine whether Kenya would move forward as a "civilised state", said a Daily Nation editorial.
Kenyans are also choosing members of parliament and senators, county governors and members of the 47 newly formed county assemblies.
Call for patience
By lunchtime on Tuesday, Mr Kenyatta of the Jubilee alliance had established a lead over Mr Odinga, who heads the Coalition for Reform and Democracy (Cord).
With 37.8% of polling stations reporting at 15:00 Nairobi time (12:00 GMT), the 51-year-old deputy prime minister had 2.53m votes, or 54%, while the 68-year-old prime minister had 1.94m, or 41%, said the website of the Independent Electoral and Boundaries Commission (IEBC).
The next nearest challenger was Musailia Mudavadi, of the Peace coalition, who trailed far behind with 131,153 votes, or 3%.
None of the other five candidates for the presidency had more than 1%. More than 250,000 spoiled ballots have also been counted so far, the IEBC noted with concern.
To win outright, a candidate must get 50% of votes cast plus one vote, as well as at least 25% of votes in half of Kenya's 47 counties. If no-one achieves that, the vote will go to a run-off, probably on 11 April.
In a news conference, IEBC chairman Issack Hassan called for people to "resist making early judgments about who has won", and said final results would not be released within 48 hours.
He said candidates and parties were under obligation to "accept the results peacefully".
There are fears the loser might not accept the official result, triggering an outburst of violence.
Widespread failure of newly instituted biometric voting kits, reports of late voting at one polling station hours after polls closed officially, and an instance of a poll clerk issuing multiple ballots have all already been cited by Mr Odinga's party as cause for concern.
"These we find to be placing in jeopardy the credibility of this process," said Frank Bett from Mr Odinga's Cord alliance.
Both leading candidates have pledged to respect the result of a free and fair vote.
Mr Kenyatta will stand trial at the ICC for his alleged role in the 2007 unrest, when supporters of the rival candidates, from different ethnic groups, took up arms against each other.
Mr Odinga later joined a government of national unity under a peace deal.
The US and other Western allies of Kenya have warned of possible "consequences" if Mr Kenyatta wins.
However, Mr Kenyatta's running mate, William Ruto, who also faces charges of crimes against humanity, insisted on Monday that they would be able to discharge their duties if elected and would co-operate with the ICC to clear their names. Both deny any wrongdoing.
Lines of voters stretched outside polling stations across the country on Monday as Kenyans chose a president, as well as members of parliament and senators, county governors, women members of 47 county assemblies, and civic leaders.
Many polling stations stayed open late into the night, and turnout was estimated at 70%.
Four policemen were among the 19 killed in election-day violence mainly blamed on the separatist Mombasa Republican Council (MRC), which had demanded the elections be scrapped.
Gunfire and explosions were also reported in the town of Garissa, near the border with Somalia. Gunmen stormed two polling stations after voting ended, but were forced to retreat by security forces, the deputy speaker of parliament told Associated Press.