Counting of election results in Kenya has slowed because of problems with the electronic systems.
Returning officers were ordered to physically deliver paper copies of the tallies from their constituency to the counting centre in the capital.
With provisional results in from more than 40% of polling stations earlier on Wednesday, Deputy Prime Minister Uhuru Kenyatta had 53% of the vote compared with 42% for Prime Minister Raila Odinga.
So far about 6% of the total votes counted are spoilt ballots - well over double the number of votes cast for third-placed candidate, Musailia Mudavadi.
President Mwai Kibaki is stepping down after two terms in office.
Some strongholds for Mr Odinga, 68, are yet to declare their results.
Mr Kenyatta, 51, is due to stand trial at the International Criminal Court next month. He is accused of fuelling the violence after the last election in 2007-08 when an estimated 1100 people were killed.