Ballot counting from this week's Kenyan general and presidential elections has been facing delays due to technical glitches in an electronic counting system, causing growing frustration over the slow pace of the count.
The country's electoral commission (IBEC) had hoped official results would come on Wednesday, but now plans to finish vote counting by late Thursday and release the results on Friday.
Instead of relying upon electronic transmission of data, electoral officials were bringing ballots from around the country to be counted manually at the main tallying centre in Nairobi on Wednesday.
The IEBC apologised for the problems in the computerised system, which cost tens of millions of dollars.
Provisional results, with more than 40 percent of votes counted, show Uhuru Kenyatta, Kenya's deputy prime minister, with about 53 percent of the vote, while his rival, Premier Raila Odinga, had about 42 percent.
To avoid a run-off, a candidate must garner at least 50 percent of the votes.
There have been indications from officials that hundreds of thousands of spoiled ballots will be counted, which would make it harder for Kenyatta to avoid a second round.
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The IEBC announced on Tuesday that those spoiled ballots will count in the overall vote total.
The commission's decision makes it very difficult, given the tight race, for either leading candidate to reach the 50 percent mark needed to win outright, raising the prospect of another round due within a month after the vote.
Kenya's 2010 constitution - passed after 2007-08 election violence killed more than 1,200 people - says a candidate needs "more than half of all votes cast in the election" to win the presidency outright or the election will be determined in a second round.
Officials close to Kenyatta, who is facing trial at the International Criminal Court (ICC) for his alleged involvement in post election violence in 2007, have accused foreign diplomats of attempting to interfere with the vote tallying.
Ban Ki-moon, the UN chief, echoed local election officials in calling for "calm and patience" as the votes were counted and urged politicians to refrain from making statements undermining the electoral commission.
"A peaceful, credible conclusion to the election is within Kenya's reach and would be a significant step for Kenyan democracy and stability," Ban said.
Kenyatta and his vice-presidential running mate, William Ruto, are among four people indicted by the ICC for their alleged roles in orchestrating the ethnically driven violence. They deny the charges.
Ruto late on Tuesday directly accused foreign diplomats of interfering with the election process.
"We know for sure that certain embassies have had positions with respect to this election," said Ruto, who was Kenyatta's opponent five years ago, but joined together with the deputy premier to form the Jubilee Coalition this year.
"We are very concerned that there is a lot of canvassing by people who should not be participants in this process and we expect that their role be limited to being observers."
Ruto said his party believes invalidated votes should not be counted into the percentages for determining the need for a run-off, possibly setting the stage for a conflict with the IEBC. His Jubilee Coalition has promised to take legal action.
Voters also made their choices for members of parliament and numerous local government posts this week. Some seats have already been decided, with politicians accepting defeat peacefully.
Kenya, with 43 million citizens, is East Africa's economic powerhouse, though many still face chronic poverty.
The country is marking 50 years of independence from Britain this year.