NAIROBI, Kenya (AP) — The leader of Kenya's main opposition party urged his supporters to boycott a rerun of the disputed presidential election scheduled for Thursday amid rising political tensions and fears of violence in East Africa's economic power.

Jubilant supporters of President Uhuru Kenyatta, who seeks a second term, celebrated the news that the election would proceed after a last-minute petition to the Supreme Court seeking to postpone the vote couldn't go forward. Kenyatta said security forces will be deployed nationwide to ensure order, and he urged Kenyans to vote while respecting the rights of those who don't.

His rival, opposition leader Raila Odinga, called on his political coalition to become a "resistance movement," accusing the president of moving a country known for relative stability and openness toward authoritarian rule.

"Do not participate," Odinga told a rally of thousands in Nairobi's Uhuru Park on the eve of the vote. The gathering was mostly peaceful, though police fired tear gas to disperse some groups of opposition supporters who occupied roads after the demonstration ended.

Protesters also set fires and blocked roads in part of Nairobi's Kibera slum, and police and demonstrators clashed throughout the day in some neighborhoods in Kisumu, Kenya's third-largest city and an opposition stronghold.

The United States urged Kenyans to remain calm on Thursday and reject violence, saying it was deeply concerned about the efforts of "both parties to interfere with and undermine the independent operation of the electoral commission, the judiciary and other essential institutions."

Kenya's Supreme Court failed Wednesday to muster enough judges to hear the last-minute petition that sought to postpone the vote, a repeat of the August election won by Kenyatta but annulled last month by the court due to what it called irregularities and illegalities.

Chief Justice David Maraga appeared alone in the courtroom and said only he and one other judge were able to attend the hearing. The driver for the court's deputy chief justice had been shot Tuesday evening, raising fears about intimidation of the judiciary.

Outside court, hundreds of women in white scarves called for peace, concerned that violence might break out as it had following the disputed election in 2007 that left more than 1,000 dead.

The petition to postpone Thursday's election pointed out that electoral officials, including the electoral commission chairman, have said they cannot ensure the vote would be free, fair and credible.

Harun Ndubi, a lawyer for the three petitioners, suggested that some judges who did not attend the hearing may have violated their constitutional duties.

"The justices must forever be available," said Ndubi, although he acknowledged that the deputy chief justice may have been genuinely troubled.

"For the others, I don't buy their explanation," he said. "I don't see a credible or legitimate election happening tomorrow."

Odinga had challenged Kenyatta's victory in August, claiming hackers had infiltrated the electoral commission's computer servers and manipulated the vote. He later shocked the country by withdrawing from the new election, saying that without reforms the vote risked having the same mistakes.

Police originally banned the Odinga rally on Wednesday but allowed it to take place. His supporters were in an almost celebratory mood, banging drums and blowing whistles and vuvuzelas as many danced.

___

Associated Press writer Mat Pennington in Washington contributed.