Kenya’s opposition has accused the government of “state terror” and vowed to overturn a “sham” result.
Senior opposition official James Orengo said they would not go to court to achieve this. He urged people to stay calm and out of harm’s way.
Mr Orengo alleged that about 100 people including children had been killed by the Kenyan security forces, and their bodies disposed of in body bags.
He offered a number of spent cartridges but little else in the way of evidence.
Official results gave President Uhuru Kenyatta 54.3%. His main challenger Raila Odinga has called the election a “charade”.
“They knew they were going to steal an election. They knew the people would be unhappy. Therefore all the instruments of violence were put in place,” Mr Orengo said.
- Kenyatta: The digital president
- Odinga: Love him or loathe him
- The men of violence making a fresh start
- Kenyans celebrate #GitheriMan voter
While journalists on the ground have not seen evidence for the scale of killings claimed by the opposition, at least 11 people are reported to have been killed by police in areas supporting Mr Odinga.
Nairobi’s city morgue said it had received eight bodies. Three people were reported to have been killed in other incidents, including a nine-year-old girl hit by a stray bullet in a Nairobi’s Mathere slum.
A man was also 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.
The Kenya National Commission on Human Rights meanwhile said 24 people had been shot dead by police during protests.
Earlier the Elections Observation Group (Elog), which had 8,300 observers, said its projected outcome put Mr Kenyatta on 54%, just short of the official figure of 54.3%
But Mr Orengo questioned Elog’s independence.
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.
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.
Kenyan media reacts – BBC Monitoring
All major newspapers in Kenya agreed that the president’s first duty should be to make real efforts to heal that were exposed during the election.
The Star newspaper said the extent of Mr Kenyatta’s victory “was surprising, even shocking, but we should accept it and move on. Kenya deserves peace and development”.
On local radio, pro-ruling party stations hosted jubilant callers. On Radio Nam Lolwe, which broadcasts to opposition areas, a caller spoke of “heartbreaking” scenes where protests had turned violent, saying: “Let us desist from violence and preach peace”.
Ramogi FM radio, which broadcasts in the Luo language of defeated candidate Raila Odinga, played gospel music – a break from the usual Saturday discussion programmes.
Kenya election: Opposition vows to overturn ‘sham’ election