Kenya’s main monitoring group has backed the official election result, which gave nearly 55% of the vote to the incumbent, Uhuru Kenyatta.
The Elections Observation Group (Elog), which had 8,300 observers, said its tally conformed to the official result.
The opposition candidate, Raila Odinga, has rejected the result, calling it a “charade”.
There has been sporadic violence, with three people reportedly killed by police in areas supporting Mr Odinga.
Elog’s projected outcome put Mr Kenyatta on 54%, just short of the official figure of 54.3%
“We did not find anything deliberately manipulated,” chairwoman Regina Opondo said.
Kenya’s acting interior minister Fred Matiang’i has urged people to return to their normal lives and called for Kenyans to use social media responsibly.
Mr Matiang’i said most areas were calm but there had been some violence which he blamed on criminals.
Those killed included a young girl who died as police shot at protesters in the Mathare area of the capital Nairobi, Reuters reported.
A man was killed in Kisumu county, an opposition stronghold and the centre of post-election ethnic violence in 2007, when 1,200 people died and 600,000 were displaced.
Mr Kenyatta has urged peace. “We have seen the results of political violence. And I am certain that there is no single Kenyan who would wish for us to go back to this,” he said.
Ahead of the results, Mr Odinga had called on his supporters to remain calm, but added that he did not control anyone, and that “people want to see justice”.
Rights group Amnesty International has called for the Kenyan authorities to investigate the killings.