Result of tight contest between Uhuru Kenyatta and Raila Odinga could be known by Wednesday morning.
Long queues formed outside polling stations across Kenya on Tuesday morning as fiercely contested presidential elections got under way following last-minute calls for calm from officials and politicians.
Many voters had waited for hours in the rain to choose between the incumbent, Uhuru Kenyatta, who has been in power since 2013, or the veteran opposition politician Raila Odinga. The most recent polls did not indicate a clear winner.
An estimated 180,000 police officers and members of the security forces have been deployed amid fears of violence after the result is announced, which may be as early as Wednesday morning.
The campaign was marred by hundreds of violent incidents – including the murder of a high-profile election official – issues with new voting technology and widespread concerns about fraud.
More than 1,100 people died after the losers rejected the election result in 2007.
In recent days bus stations have been busy as many Kenyans have left major cities for provincial areas which are seen as safer. Others have stockpiled groceries, phone cards and other essentials.
Election officials have circulated short videos on social media calling on voters to accept that in a “healthy democracy there are winners and losers”.
Kenyatta, 55, addressed the nation on Monday night, urging citizens to vote “in peace” while the former US president Barack Obama, whose father was born in Kenya, led international calls for a violence-free election.
“I urge Kenyan leaders to reject violence and incitement; respect the will of the people,” Obama said in a statement.
There are more than 19 million registered voters in the nation of 48 million. Half are aged under 35. They will vote in 40,000 polling stations.
Pamela Mwande, 33, said she had voted for Kenyatta in the upscale Lavington area of Nairobi.
“[The president] has been a good leader. We should not have change and disruption and fuss,” she said.
Observers see the election as the last showdown of a dynastic rivalry between the families of Kenyatta and Odinga, 72, that has lasted more than half a century.
The presidential candidates’ fathers – Jomo Kenyatta and Jaramogi Oginga Odinga – fought together for independence from Britain in 1963 before becoming bitter rivals.
Odinga is making his fourth attempt to gain power. He claims that elections in 2007 and 2013 were stolen from him.
The men belong to two of the country’s main ethnic groups, Kenyatta from the Kikuyu, the largest, and Odinga from the Luo.
Both have built coalitions with other influential communities in a country where voting still takes place largely along ethnic lines.
Kenyatta’s first term saw a massive infrastructure drive and steady economic growth of more than 5%, making Kenya one of the best performing economies in Africa.
However his record has been undermined by soaring food prices, ongoing high unemployment and major corruption scandals.