Kenyan President Mwai Kibaki trailed his main rival today in the race to lead east Africa's biggest economy for the next five years, according to early tallies by local media.
Partial results from three main television stations all gave opposition challenger Raila Odinga - the son of a nationalist hero - a strong lead over his former ally, although a separate exit poll put Kibaki ahead in what many had forecast would be Kenya's closest ever election.
Were Odinga to win, this would make Mr Kibaki the first of Kenya's three sitting presidents to be ousted by the ballot box in the 44 years since the end of British colonial rule.
The unofficial results by the TV channels were compiled from tallies at counting centres. The latest, from KTN earlier, gave Mr Odinga 1,862,573 votes to 1,179,271 for Mr Kibaki - representing about a third of ballots believed cast.
About 14 million Kenyans were eligible to vote, although turnout is expected to have been between 8 and 10 million.
As official counts slowly reached a Nairobi conference centre ringed by armed guards, the Electoral Commission of Kenya (ECK) said provisional results would be announced throughout today, but that the process could stretch into Saturday.
"There's no excuse for our field officers not to have sent us results that were announced by the media two hours ago," said ECK Commissioner Jack Tumwa. "The country is getting restless."
Officials had earlier given the outcome from just two of Kenya's 210 constituencies. One chose Mr Odinga and the other picked the president, both by large majorities in a reflection of the country's deeply entrenched Kenyan tribalism.
The ECK said turnout looked to be the highest since multiparty politics was reintroduced in 1992. International observers said Thursday's voting had gone smoothly, despite sporadic violence and allegations of rigging by both sides.
"The test for our democratic maturity is in the post-election period and how we conduct ourselves thereafter," police boss Hussein Ali told a news conference.
"For the winners, we trust you will exercise magnanimity. For the losers ... you can try another time."