NAIROBI, Kenya — After his fellow commissioner fled the country, citing threats to her life, Kenya’s top election official on Wednesday accused the nation’s political parties of undermining the country’s stability and warned that he was not confident that next week’s presidential election would be credible.

Kenyans are scheduled to vote — again — for president on Oct. 26. The nation’s current president, Uhuru Kenyatta, handily won the first election in August, beating the veteran opposition leader, Raila Odinga, by 1.4 million votes.

But Mr. Odinga turned to Kenya’s Supreme Court, arguing that the vote had been manipulated to assure the president’s victory. To the nation’s surprise, the court ruled that the vote was flawed and, in a first for Africa, annulled the results, paving the way for a new election.

Still, Mr. Odinga said he would withdraw from the race anyway, insisting that the Independent Electoral and Boundaries Commission was deeply biased against him and would not be able to fix its underlying problems by election day.