Kenyan police in Nairobi have used water cannons, tear gas and clubs to disperse scores of demonstrators demanding constitutional reform.
Riot police on horse back and on foot chased protesters, as they approached a Nairobi city park where a rally was supposed to be held Saturday.
The Kenyan government banned the event Friday, saying it feared violence.
Critics of Kenyan President Mwai Kibaki accuse him of deliberately delaying the introduction of a new constitution that would decrease his powers and give more executive responsibility to the newly-created post of prime minister.
Mr. Kibaki blames the delays on court challenges to the charter.
Kenya's political factions - including those within the ruling party - are sharply divided over the draft of the constitution.