Former US president Barack Obama led international calls for peace Monday ahead of Kenyan elections seen as too close to call, with fears that violence could flare in east Africa's richest economy.

Kenyan President Uhuru Kenyatta gave a televised election-eve speech aimed at easing tensions, after a final campaign week marred by rigging accusations levelled by his bitter rival Raila Odinga, and the murder of a top election official.

Kenyatta, who is seeking a second and final term in office, urged the 19 million registered voters to turn out in great numbers, but to "do so in peace".

"After you cast your ballot, please go home," he said, urging Kenyans to reject a repeat of the post-election violence a decade ago that left more than 1,100 people dead and 600,000 displaced.

"Go back to your neighbour. Regardless of where he or she comes from, their tribe, their colour or their religion... Shake their hand, share a meal and tell them 'let us wait for the results,' for Kenya will be here long after this general election," said Kenyatta.

Obama, whose father was born in Kenya, joined former South African president Thabo Mbeki -- who is leading the African Union's monitoring of the election -- and former US secretary of state John Kerry in calling for a peaceful and untainted election.

"I urge Kenyan leaders to reject violence and incitement; respect the will of the people," Obama said in a statement.

UN human rights experts expressed concern at "the rise of hate speech" in the run-up to the vote.

- 'Worthy opponent' -

Like the president, Kenyatta's historic rival Odinga addressed voters on Monday, again raising concerns about rigging and warning that the deployment of at least 150,000 security forces across the country was meant to intimidate voters.

However, he congratulated his "worthy opponent" on his campaign.

"May the stronger candidate win tomorrow," said Odinga, who has run unsuccessfully for the presidency on three occasions.

The polls are seen as a litmus test of Kenya's progress since the disputed 2007 vote that sparked two months of bloodshed.

The men belong to two of the country's main ethnic groups, Kenyatta from the Kikuyu, the largest, and Odinga the Luo. Both have secured formidable alliances with other influential communities in a country where voting takes place largely along tribal lines.

In the run-up to the election both Kenyatta and Odinga refrained from making inflammatory speeches, observers say, perhaps a consequence of the International Criminal Court's now-abandoned indictment of Kenyatta and his running-mate William Ruto for their alleged roles in the 2007 bloodshed.

But hate speech flyers and text messages have been circulating, making Kenyans nervous.

Elections in 2013 were largely peaceful, although Odinga did accuse Kenyatta's Jubilee Party of poll fraud after massive glitches with the electronic voting system.

On Tuesday Kenyans will cast ballots in six different elections, choosing governors, lawmakers, senators, county officials and women's representatives in local races also rife with tension.

Source: AFP