Though the majority of the voting went ahead without incident, at least three people were killed, The Associated Press said, including a 17-year-old who died of gunshot wounds, according the head nurse at a government hospital in the western city of Kisumu.

The confrontations between the police and rock-throwing protesters who wanted to stop the vote prompted the authorities to postpone balloting until Saturday in four districts affected by the violence.

President Uhuru Kenyatta is expected to win the election, since his main challenger dropped out.

Mr. Kenyatta’s main challenger, Raila Odinga, had accused the president of fraud and dropped out of the race, saying that he believed the second election would be "worse than the previous one” because the electoral commission had not made changes to its operation or its staffing.

But Mr. Odinga did not file the paperwork that would have formally removed him from the race, so his name appears on the ballot, according to election commissioners.

The first election, on Aug. 8, was nullified by the Supreme Court, which cited irregularities. The political crisis deepened on Wednesday, when the court was unable to hear a case that could have delayed the election after only two of the seven judges showed up. Five are needed for a quorum, Chief Justice David Maraga said.

The mood in some parts of the country remained tense on Thursday. Mr. Odinga had urged supporters to boycott the vote, raising the dangerous prospect that millions of his supporters will not acknowledge the outcome.

Protesters began gathering in Kisumu and Nairobi’s Uhuru Park since Wednesday to demonstrate against the looming ballot. On Twitter, the main opposition group, the National Super Alliance, warned, "The primary responsibility, if the worst occurs, lies squarely with Kenyatta.”

In anticipation of demonstrations during the second round, the Kenyan police said they would not allow the National Super Alliance to hold a rally at the capital’s Freedom Park ahead of its boycott. But the rerun of the vote erupted in clashes, with the police firing tear gas at rock-throwing protesters in the Nairobi neighborhood of Kibera.

New York Times