Kenya's defeated presidential contender Raila Odinga filed a legal challenge to his election loss today in a major test of the country's democracy five years after a disputed vote triggered deadly tribal violence.
Shortly before, police outside the Supreme Court used teargas to break up a rally of around 100 Odinga supporters, who were urged by the outgoing prime minister to stay calm and trust in the law to resolve his complaint.
Mr Odinga's petition threatens to extend the period of uncertainty shadowing east Africa's largest economy.
The outgoing prime minister refuses to accept the slim first-round election win by Uhuru Kenyatta, who has been indicted by the International Criminal Court over the 2007 bloodletting in which more than 1,200 people were killed.
The March 4th vote was largely peaceful by contrast, and Mr Kenyatta declared it "free and fair" in his acceptance speech last Saturday, though he added that the electoral process could be made more refined and efficient in the future.
Kenya's electoral commission (IEBC) had promised a smooth election but the collapse of an expensive new electronic voting system led to a five-day wait for the winner to be announced.
Mr Odinga's petition alleges widespread rigging and accuses the IEBC of inflating voter registration numbers and going ahead with the election aware that its systems were going to fail.
"These failures dwarf anything Kenyans have ever witnessed in any previous election," Mr Odinga told reporters on the doorstep of his office in the centre of the capital Nairobi.
"Every mechanism and every instrument the IEBC deployed failed miserably. Its failure and collapse, on a catastrophic scale on the polling day, so fundamentally changed the system of polling and the number of votes cast."
Kenyatta comfortably beat Odinga in terms of votes won, 50.07 percent versus 43.28 percent, but only narrowly avoided a run-off after winning just 8,100 votes more than the 50 percent needed to be declared the winner outright.
The tight nature of Kenyatta's win has given Odinga allies confidence that they can force a run-off through the courts, though the petition calls for the whole process to be declared null and void.
By the time the petition was filed in the early afternoon, hundreds of Mr Odinga supporters gathered outside the court, many wearing T-shirts with slogans such as "democracy on trial".
"I am not happy with the election results, since my rights have been stolen. President-elect Uhuru Kenyatta is not my choice," Florence Bolo, an Odinga supporter, said outside the Supreme Court. Others shouted: "Uhuru must go!"
Traffic was moving freely through Nairobi and there were no signs of further unrest in the capital.
Many had feared a repeat of the 2007 violence after this month's vote, and were relieved when that did not transpire.
But analysts say a swift, transparent resolution of the dispute will be critical to restoring Kenya's reputation as a stable democracy. Big Western donors worry about a nation seen as a vital ally in the regional fight against militant Islam.