Five things to know about Kenya's election

Kenyans are heading to the polls on Tuesday, in a close presidential election between incumbent President Uhuru Kenyatta who seeks a second term and Raila Odinga.

The East African nation is often described as one of the continent's most politically stable countries. However, some Kenyans are worried by memories of the violent months that followed the 2007 vote and say there could be trouble ahead.

Here are five things to know about the country and its election:

1. Why are Kenyans nervous about the election?

Opinion polls suggested Kenyatta and Odinga, who is fighting his fourth presidential election, are neck-and-neck, leading many Kenyans to fear a disputed result and possible violence.

These concerns have been intensified further after Odinga told Reuters that Kenyatta could only win by rigging the vote.

2. What happened the last time?

Worries like these are common around election time in Kenya.

Kenya's last election, in 2013, passed off peacefully. But 10 years ago, the country was plunged into widespread violence in the aftermath of the 2007 vote.

More than 1,000 people were killed and 500,000 were displaced in months of chaos following the election, after Odinga – who had been defeated by the then-president Mwai Kibaki – claimed the vote had been rigged.

After more than a month of negotiations, former United Nations Secretary-General Kofi Annan mediated a power-sharing agreement in February 2008 that was signed by both leaders.

In March 2013, Kenyatta, defeated Odinga, despite charges of crimes against humanity by the International Criminal Court (ICC) over the 2007-2008 violence.

The court dropped its case against him in December 2014 due to lack of evidence.

3. Who are the candidates?

There are eight candidates vying for the presidency. But only Kenyatta and Odinga, two men whose fathers led Kenya to independence almost 55 years ago, retain any real hope of winning.

Kenyatta, who has been president since 2013, is son of the country's first president, Jomo Kenyatta. He has promised to create 1.3 million new jobs, reduce the cost of living and create a more inclusive economy by reducing economic inequalities.

Odinga is son of the Kenya's first vice president Jaramogi Oginga Odinga. He has promised to fight corruption, create jobs for young people and set up programs to improve food security.

Under the new constitution passed in 2010, a presidential candidate must win a minimum of 25 percent of the votes in at least 24 of the 47 counties to secure the presidency. This measure is designated to force powerful groups to build alliances with smaller tribes.

If no winner is declared, the election will go to a runoff, which would be a first in Kenya's history.

4. The tribe or the ballot box?

Most political organising in Kenya is tied to ethnicity. Kenyatta and Odinga are from storied political families.

Many voters see Kenyatta as the candidate of the Kikuyu people, the country's largest ethnic group, while Odinga is seen as representing the Luo. That the Luo have never produced a head of state adds drama to the election.

Although the country remains dominated by tribal politics, reforms aimed at fostering ethnic inclusion are bringing some small, gradual changes.

Kenya's president and opposition leader both held election rallies outside their ethnic strongholds this week, as the candidates push harder to win votes in areas dominated by their rivals.

Many Kenyans still vote along ethnic rather than policy lines, but Kenyatta and Odinga have both signalled they are seeking support across the country's many communities.

"We do not move on tribal lines," Kenyatta told a cheering crowd in the eastern town of Kitui on Thursday. "It is my government's pledge to develop all parts of the country, regardless of region and tribe."

5. Why is Kenya's stability important to the whole continent?

Kenya is one of east Africa's leading economies and the main trading hub in the region.

Kenya's stability matters to the whole continent thanks to its more advanced human capital base, its more diversified economy and its role as a leader in the information communication revolution in the region.

Any unrest in this country would affect neighbouring economies.