Several people were injured as police engaged youth who blocked roads in the southwestern city and threw stones, Nyanza regional police boss Leonard Katana said. Police used tear gas to disperse them, he said.
The Kenya Television Network reported that youth stormed a meeting of women from various religious groups at a local hotel as they discussed how to ensure a peaceful election. The women told KTN that the youth beat them up and stole their phones before police intervened.
Kenya will hold a repeat presidential election on October 17 after the Supreme Court nullified President Uhuru Kenyatta's re-election last month. Opposition leader Raila Odinga went to court claiming electoral fraud.
Odinga has repeatedly said he won't participate in next month's vote unless changes are made to the East African nation's electoral commission, which the court said had committed irregularities.
On Wednesday, a principal member of Odinga's coalition said opposition members of parliament will boycott all parliamentary activity until the new election. Moses Wetangula called the current chamber "devoid of any legality."
Civil society activists demonstrated in the capital, Nairobi, to push the electoral commission's top officials to resign.
"There must be action around officials who are associated with electoral offenses. We cannot go for a new round of elections without having action on these officials and they cannot conduct new elections," said Gladwell Otieno, executive director of the Africa Center for Open Governance.