At least one person was shot dead at a protest against Kenya's election body in the western city of Kisumu on Monday and others wounded, hospital officials said, as demonstrators also gathered in the capital.
Police fired into the air to break up a crowd trying to march on the Kisumu office of the Independent Electoral and Boundaries Commission (IEBC), one witness told Reuters.
Protesters, accusing the commission of pro-government bias and demanding its members resign before elections in August next year, blocked roads with burning tyres in Kisumu and in Nairobi's Kibera slum. Demonstrators also marched in the centre of the capital, blocking traffic. "IEBC must go," they shouted.
Dennis Onyango, spokesman for opposition leader Raila Odinga who led Monday's rally in Nairobi, said two people were killed in Kisumu. But hospital officials said they only knew of one.
Juliana Otieno, superintendent at Jaramogi Oginga Odinga Teaching and Referral Hospital, said 12 casualties with bullet wounds had been admitted to her hospital, while she said Kisumu County hospital reported one dead and others with bullet wounds. A nurse at Kisumu hospital also confirmed one dead there.
There was no immediate police comment on Monday's reported deaths. Kenyan television reported at least one person killed.
Western Kenya, traditionally an opposition stronghold, has seen some of the worst violence in the almost weekly protests. Three people were killed in clashes in the region on May 23.
Western ambassadors have accused the police of using excessive force and called for dialogue in a nation prone to political strife. The 2007 election triggered weeks of ethnic bloodshed and the 2013 result was disputed.
A meeting last week between President Uhuru Kenyatta and opposition leader Raila Odinga failed to defuse tensions.
Police said on Friday that any march by protesters would contravene a court order and demonstrators could face arrest. Despite the warning, the protest in Nairobi proceeded calmly without clashes with police that were seen previously.
Businesses have called for a swift resolution of the row, saying it was taking a toll on an economy which was hit hard by the post-2007 election violence amid the tensions in the build up to the 2013 vote.
"We must find solutions and the solution must be based on the rule of law. It calls for a lot of mediation," Kenya Private Sector Alliance (KEPSA) Chairman Dennis Awori told Reuters, urging churches, politicians and others to help bring calm.
IEBC commissioners deny any bias and say they will stay on, while the government has said any reform needs to follow constitutional channels, which could involve a petition to parliament where Kenyatta's Jubilee coalition has a majority.