Kenya's opposition leader Raila Odinga has said he will not share power, days after the Supreme Court's decision to annul President Uhuru Kenyatta's re-election and order a fresh election in 60 days.
Mr Odinga, speaking at a church service in Nairobi on Sunday, said his party cannot accept sharing power with "thieves".
President Uhuru Kenyatta similarly ruled out sharing power when addressing elected members of county assemblies from his Jubilee Party on Saturday.
Mr Odinga, 72, was named prime minister and Mr Kenyatta his deputy in a coalition government in February 2008 following the disputed presidential election of December 27, 2007.
More than 1,000 people died and 600,000 were evicted from their homes in post-election violence that erupted from that election.
The Supreme Court nullified Mr Kenyatta's win announced by the electoral commission on August 11.
The court voted 4-2 to nullify Mr Kenyatta's election, saying they found the electoral commission had performed irregularities and illegalities in adding up the presidential vote.
Mr Odinga said the electoral commission as currently constituted should not be permitted to conduct the fresh election, saying it was complicit in electoral fraud.
Mr Kenyatta, however, has said the electoral commission should not be interfered with and warned the court against taking action on the Independent Electoral and Boundaries Commission.
Since the Supreme Court ruling Mr Kenyatta has said chief justice David Magara and the judiciary are "crooks" and alleged they are on the payroll of donors.
Mr Kenyatta said he will fix the judiciary once he wins the coming elections because it ruled against him.
The move to nullify Kenya's election was unprecedented on the African continent.
It gave new hope to opposition leader Mr Odinga, who had alleged the electronic results of the August 8 balloting were manipulated. He had lost by about 1.4 million votes out of roughly 15 million ballots cast.
Mr Odinga, a longtime opposition candidate and the son of Kenya's first vice president, had unsuccessfully challenged the results of the 2013 vote that Mr Kenyatta won.
This time Mr Odinga's supporters at first had said they would not go to court but filed a petition two weeks ago.
Kenya had been braced for protests before the ruling, with police deployed to sensitive areas of the capital, Nairobi, and streets near the court were barricaded.
Human rights groups have said that police killed at least 24 people in unrest after the election.
Mr Kenyatta, 55, the son of Jomo Kenyatta, Kenya's first president, is trying to avoid becoming the first Kenyan president not to win re-election.