National Super Alliance (Nasa) presidential candidate Raila Odinga says they are moving to the Supreme Court to contest President Uhuru Kenyatta win in August 8 poll.
Mr Odinga on Wednesday termed as "computer-generated", Mr Kenyatta's victory as declared by the Independent Electoral and Boundaries Commission (IEBC).
He said their decision to fight Mr Kenyatta in court was partly informed by the ongoing crackdown on pro-democracy civil societies, including the Africa Centre for Open Governance and Kenya Human Rights Commission.
Their mission in the top court in the land, Mr Odinga said, is to "demonstrate to the whole world the making of a computer-generated president".
"We will show the world how the figures were cooked and Uhuru Kenyatta declared the winner," Mr Odinga said at Okoa Kenya offices in the capital Nairobi.
"Kenyans will not agree to be led by computer-generated leaders."
Mr Odinga said the Supreme Court has the opportunity to redeem itself and give Kenyans justice— an apparent reference to the court’s decision in 2013 that saw him lose.
The court dismissed his case on the March 4 presidential poll that IEBC said Mr Kenyatta won, citing lack of evidence.
"We want to show the world what transpired... how figures were cooked and non-existent polling stations," Mr Odinga said.
Nasa, he said, has evidence to prove how results were inflated in order to give Mr Kenyatta undeserved victory.
Results streamed by the IEBC were not backed by forms 34B, the documents signed by party and candidates' agents in constituencies, the opposition leader said.
He particularly queried Mr Kenyatta's 11 percent "consistent lead" in the results posted on IEBC web portal, terming it "the work of a computer algorithm".
"Yesterday (Tuesday) Chiloba admitted that all forms 34B were not in and, therefore, results were null and void," he said, referring to IEBC CEO Ezra Chiloba.
"Uhuru wasn't supposed to be declared as the winner."
His comment came hours after the commission, in a Twitter post, said forms 34B for all constituencies were available to the public to scrutinise the results.
According to results announced by IEBC Chairman Wafula Chebukati on August 11, Mr Kenyatta garnered 8,203,290 votes, representing 54.27 per cent of the votes cast.
Mr Odinga, the ODM and Nasa candidate, came in second with 6,762,224 votes, representing 44.74 per cent of the votes cast.
Mr Kenyatta also garnered more than 25 per cent of the votes cast in 35 counties, compared to Mr Odinga who got over 25 per cent in 29 counties, Mr Chebukati said.
In total, 15,073,662 people cast their votes, representing 78.91 per cent of the registered voters.
The results sparked protests and demonstrations in Nasa strongholds in the capital Nairobi and Luo Nyanza, leading to the deaths of over two dozen people, according to Kenya National Commission on Human Rights.
Police and the government have disputed the death toll, putting the count at 10.
Mr Odinga's decision to challenges the results in court came after days of sustained local and international pressure on him to ask his supporters to leave the streets and contest Mr Kenyatta's win through legally allowed avenues.
The pressure came from, among others, the UN, the US, the EU, the Kenyan government, politicians and local religious and human rights organisations.
The Nasa leader was accompanied by his running mate Kalonzo Musyoka and opposition chief agent Musalia Mudavadi and his deputy James Orengo.