Kenyans cast ballots on Thursday in the second presidential election in nearly three months amid a boycott by the main opposition leader and clashes in some areas that turned deadly.

Though the majority of the voting occurred peacefully, at least four people were killed, The Associated Press said. The dead included a 17-year-old who died of gunshot wounds, Henry Omosa, the head nurse at a government hospital in the western city of Kisumu, told the news media. The police also fired tear gas at rock-throwing protesters in the Nairobi neighborhood of Kibera.

Amid confrontations between the police and rock-throwing protesters who wanted to stop the vote, the authorities postponed balloting until Saturday in four districts.