Kenyan police fired teargas at hundreds of opposition supporters in the capital Nairobi calling for the sack of some electoral commission officials.
The demonstration is part of the weekly protests in several cities scheduled by the National Super Alliance (NASA) party led by Raila Odinga to demand reforms at the Independent Electoral and Boundaries Commission (IEBC).
They want the IEBC CEO Ezra Chiloba and other commissioners to be sacked for allegedly rigging the August 8 elections in favour of the ruling Jubilee party.
Last week, the protesters in the port city of Kisumu burned car tyres, blocked roads and lit bonfires before the police shot tear gas to disperse them as they planned marching to the electoral commission offices.
The police said the protesters were not given approval and were informed not to hold the demonstration due to security concerns.
The protests are also being held in Kakamega, Mombasa, Homa Bay and Kisumu where security has been beefed up to stop the protesters.
NASA leader and presidential candidate Raila Odinga has warned the police not to attack or stop protesters from exercising their rights.
He vowed that until their demands are met, there will be demonstrations every Monday and Friday, and they will not be ready for the October 26 election re-run.
President Uhuru Kenyatta has also called on the public to ignore calls to demonstrate.