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.

Kenyans, meanwhile, are on edge. Renewed campaigning is growing even more heated as voting day approaches. On Tuesday, Mr. Odinga called off protests in Nairobi’s city center, alleging that his supporters were the targets of police violence. Human rights groups say that nearly 70 people have been killed across the country in the wake of the original election.

The death of Chris Msando, the electoral commission’s top digital security officer who was killed a week before the election, remains unsolved. And on Wednesday, an election commissioner resigned, citing death threats against her.

“Ironically the very people — the political leaders — that are supposed to build the nation have become the greatest threat to the peace and stability of the nation,” the top election official, Wafula Chebukati, said Wednesday.

Mr. Chebukati, the chairman of the electoral commission, warned that he could not “truly be confident of the possibility of having a credible presidential election” unless the feuding political parties agreed to dialogue and members of the election commission renounced their “partisan political interests.”

Mr. Chebukati’s comments came only hours after a member of the election commission, Roselyn Akombe, announced her resignation from New York, where she had fled because of anonymous threats. She had been scheduled to help preside over a commission delegation supervising the printing of ballot papers in Dubai, but she said she secretly booked a connecting flight from Dubai to New York in order to resign.

“I couldn’t say those things and remain in the country,” she said by telephone. “It’s not unfounded. We still have the unresolved brutal murder of Chris Msando, and I worked very closely with him.”

Ms. Akombe said it was impossible, at this point, to hold a credible election next week. She said the two feuding parties needed to negotiate their way out of what she called “a political crisis” and “stop the grandstanding” if the vote was to have any legitimacy.

Mr. Odinga’s public refusal to participate complicates that matter. Though he said he was withdrawing, Mr. Odinga never filed the form that legally removes him from the race. An election commissioner told a local newspaper, The Standard, that Mr. Odinga’s name appeared on ballot papers being printed this week in Dubai.

“Odinga’s withdrawal essentially deprives the election of its legitimacy,” said Patrick Gathara, a Kenyan political analyst. “Right now we have a political crisis, not a constitutional one. There’s still time for a political solution that allows us to postpone this election.”

The president, Mr. Kenyatta, has insisted that the vote take place as scheduled, and Deputy President William Ruto told reporters on Tuesday that the governing party would not agree to any dialogue with the opposition before a vote took place.

“Then we will be in a circus forever,” Mr. Ruto said in a news conference in Nairobi.

In “the actual election” in August, “we won fair and square,” Mr. Ruto said. “I think that is where legitimacy lies.”

Ms. Akombe said the consequences of holding the vote could be dire.

“I share that fear, that if we proceed with elections on the 26th of October, there’s no way we can avert violence,” she said.

The chairman of the electoral commission, Mr. Chebukati, bluntly denounced political leaders from both sides for mangling the process and risking what appears, at the moment, to be a fragile peace.

“If Kenya burns, it will be because we have not addressed these issues,” he said. “Never forget the fact the people for whom it burns all have the resources to relocate their families abroad in a minute.”