The election commission says Kenyatta won Tuesday's election with 54.27 percent of the vote.
The announcement of the results was delayed for hours, after election officials said they needed time to review some documents from some polling districts. Both are sons of late independence fighters: Kenya's first president Jomo Kenyatta and his deputy, Oginga Odinga.
More than 15 million people cast their ballots representing 78 percent of the registered voters.
"The process is still underway".
"Those of us who are friends of Kenya and who believe that peaceful election in Kenya, like in any other African country, is necessary to stabilise democracy in Africa and lay the foundation for strong economic development, unity and progress are also anxious", he said.
Kenyan laws require that results be signed off by electoral officials and party agents at polling stations, and sent to 290 constituency offices, where they must be collated before being forwarded to a national counting center to determine the final tallies.
"He is not accepting the results and that is why we are on the streets, but police have started shooting", said demonstrator Sebastian Omolo in Kisumu, one of Kenya's largest cities. He urged Kenyans to reject the results. Odinga's rejection of the tally fueled tensions among opposition supporters fearful of a stolen election, and raised fears a disputed result could trigger violence. The post election violence left over 1,000 people dead and thousands displaced.
"We do not want to see any violence in Kenya".
"Kenyans want us to succeed". "I don't control the people but I have asked them to remain calm", he told journalists. "We also hope that the security forces are not going to use excessive force".
The Chairperson of the AU Commission is in contact with regional leaders and other members of the worldwide community to ensure a coordinated and effective support to efforts aimed at preserving peace, security and stability in Kenya and upholding the principles of the rule of law and democracy, according to the statement.
On Thursday, Nairobi appeared to be somewhat quieter than usual, possibly because of school holidays and some concern from residents about potential violence. Businesses have been closed in Nairobi's central business district since Tuesday's vote.
Kenya's election commission earlier delayed the announcement of final Presidential results, saying they are ensuring they get it right before acting after a hotly-contested vote.
Marietje Schaake, head of the mission, said the European Union would provide an analysis of the tallying process in a later report.
Odinga claimed that this was due to hacking, but the claim had been denied by the Independent Electoral and Boundaries Commission (IEBC). Those charges were later dropped for lack of evidence, and Kenyatta ran for president in 2013, making his defiance of the ICC one of his campaign's centerpieces.
Commission chief Wafula Chebukati said Wednesday he did not know whether the system had been hacked but vowed to investigate the claim.