Defeated presidential candidate Raila Odinga also calls the election outcome "a travesty and a blatant disregard of the constitution".

Odinga has stopped short of explicitly announcing that he will mount a challenge at the Supreme Court.
Odinga has stopped short of explicitly announcing that he will mount a challenge at the Supreme Court. (AFP)

Kenya's defeated presidential candidate Raila Odinga has vowed to pursue "all constitutional and legal options", after rejecting the outcome of elections that awarded victory to his rival William Ruto.

The 77-year-old veteran politician branded the result of the August 9 race a "travesty" on Tuesday, but stopped short of explicitly announcing that he would mount a challenge at the Supreme Court.

"What we saw yesterday (Monday) was a travesty and a blatant disregard of the constitution and the laws of Kenya," he told a press conference in Nairobi, blaming the head of the commission that oversaw the poll.

"I do not want to fully address our strategies going forward but...we will be pursuing all constitutional and legal options available to us."

Odinga narrowly lost his fifth bid for the top job to Deputy President Ruto, who was proclaimed president-elect on Monday after a nail-biting wait for results.

His supporters had cried foul over the outcome, which also triggered divisions in the Independent Electoral and Boundaries Commission (IEBC), which issued the results.

Odinga lost by around 230,000 votes despite the support of his old foe, the outgoing President Uhuru Kenyatta, and the weight of the ruling party machinery behind him.

READ MORE: Violent protests erupt in Kenya after deputy president Ruto wins election

Claims of rigging

The poll's aftermath is being keenly watched as a test of democratic maturity in the East African powerhouse, where past elections have been tarnished by claims of rigging and bloodshed.

No presidential poll outcome has gone uncontested in Kenya since 2002 and Odinga says he was already cheated of victory in the 2007, 2013 and 2017 elections.

In August 2017, the Supreme Court annulled the election after Odinga rejected a Kenyatta victory. Dozens of people were killed by police in post-poll protests.

Kenya's worst electoral violence occurred after the 2007 vote, when more than 1,100 people died in bloodletting between rival tribes.

On the campaign trail, both frontrunners pledged to resolve any disputes in court rather than on the streets.

Violent protests nevertheless erupted in Odinga's strongholds in Nairobi slums and the lakeside city of Kisumu on Monday evening, although the situation was calm on Tuesday.

Odinga commended his supporters "for remaining calm and keeping the peace". 

Ruto, the 55-old deputy president, was conciliatory in his victory speech on Monday.

"I will work with all leaders in Kenya so that we can fashion a country that leaves nobody behind," Ruto said, pledging to run a "transparent, democratic, open government".

READ MORE: Kenya’s William Ruto: From selling chickens to vows of nation building

Source: AFP