Kenya's defeated presidential candidate Raila Odinga filed an online petition to the country's top court on Monday challenging the result of the August 9 election that handed victory to his rival William Ruto.
Odinga, a veteran opposition leader who ran with the backing of the ruling party, has rejected the outcome of the poll, branding it a "travesty."
He narrowly lost to Ruto by around 230,000 votes -- less than two percentage points.
"It has already been sent to them and they will see it soon," Daniel Maanzo, a member of the 77-year-old politician's legal team, said of the petition.
"We have hopes that we have made a good case and will win," he added.
Paul Mwangi, who is also representing Odinga, told AFP that a physical copy of the petition would be filed before the Supreme Court's 2 pm (1100 GMT) deadline.
Although polling day passed off peacefully, the announcement of the results a week ago sparked angry protests in some Odinga strongholds and there are fears that a drawn-out dispute may lead to violence in a country with a history of post-poll unrest.
Since 2002, every presidential election in Kenya has triggered a dispute, with this year's outcome also causing a rift within the Independent Electoral and Boundaries Commission (IEBC) which oversaw the poll.
Odinga, who was making his fifth bid for the top job, also approached the Supreme Court in August 2017, when President Uhuru Kenyatta was declared the winner of the presidential race.
The court annulled that election in a first for Africa and ordered a re-run which was boycotted by Odinga. Dozens of people died during a police crackdown on protests.
Judges now have 14 days to issue a ruling. If they order an annulment, a new vote must be held within 60 days.
- 'We want justice' -
Hundreds of Odinga supporters gathered outside the court on Monday, blowing whistles and waving placards reading "Electoral Justice Now!" and "We want justice now".
"Odinga must win so that we get the 6,000 shillings ($50) promised in his manifesto," said one man, wearing a crown made with plants who was referring to a monthly cash handout for vulnerable households.
Another man -- armed with a Bible and wearing huge green glasses -- knelt down in prayer as police guarded the court premises.
Judges are also expected to consider other challenges against the result, with a court clerk telling reporters the tribunal had already received one petition filed by a voter.
Odinga, who buried the hatchet with Kenyatta in 2018, winning the president's backing for his candidacy, said last week that the figures announced by the IEBC were "null and void and must be quashed by a court of law".
The IEBC was under heavy pressure to deliver a clean vote after facing sharp criticism over its handling of the August 2017 election.
But in a shock development shortly before the results were announced, four of the IEBC's seven commissioners accused chairman Wafula Chebukati of running an "opaque" operation and later said the numbers did not add up.
Chebukati dismissed the claims, insisting he had carried out his duties according to the law of the land despite "intimidation and harassment".
- Divided opinion -
Legal experts are divided on whether Chebukati needed the commissioners' backing to announce the results, with constitutional lawyer Charles Kanjama telling AFP there was "some ambiguity" surrounding the issue.
Odinga has previously said he was cheated of victory in the 2007, 2013 and 2017 elections, and the poll's aftermath is being keenly watched as a test of democratic maturity in the East African powerhouse.
On the campaign trail, both frontrunners pledged to resolve any disputes in court rather than on the streets.
Since the results were declared, Odinga has commended his supporters for "remaining calm" while Ruto has taken a conciliatory tone and promised to "work with all leaders".
Kenya's worst electoral violence occurred after the 2007 vote, when more than 1,100 people died in politically motivated clashes involving rival tribes.
If the Supreme Court upholds the results, Ruto will become Kenya's fifth president since independence from Britain in 1963, taking over the reins of a country battling surging inflation, high unemployment and a crippling drought.