STORY: Kenya's veteran opposition Raila Odinga filed a challenge to the results of this month's presidential election in the Supreme Court on Monday (August 22).
That's according to his legal team and a source at the judiciary.
It sharpens a political clash that has gripped East Africa's powerhouse.
Last week, the election commission declared Deputy President William Ruto had won the election by a slim margin, with Odinga close behind.
But four out of seven election commissioners disowned the count, saying it wasn't transparent.
Last week, Odinga said the results were a "travesty" but said he would settle the dispute in court and urged supporters to remain peaceful.
This is Odinga's fifth stab at the presidency; he blamed several previous losses on rigging. Those disputes triggered violence that claimed more than 100 lives in 2017 and more than 1,200 lives in 2007.
In 2017, the Supreme Court overturned the election result and ordered a re-run, but Odinga boycotted it, saying he had no faith in the election commission.
This time, Odinga is backed by the political establishment, including President Uhuru Kenyatta, who fell out with Ruto after the last election.
At stake is control of East Africa's wealthiest and most stable nation, home to regional headquarters for firms like General Electric, Google, and Uber.
Kenya also provides peacekeepers for neighboring Somalia and frequently hosts peace talks for other nations in the turbulent East Africa region.
Petitioners must submit their complaint to the Supreme Court within seven days of the results being declared.
The constitution requires the nation's highest court to issue its decision within 14 days of the lawsuit being filed.