Kenyan riot police were out in force Monday for a day of action called by the opposition to protest the country's cost of living crisis, despite a ban on the demonstrations.
They also have fired tear gas and used a water cannon on the opposition leader's convoy.
In one part of Nairobi's biggest slum Kibera, demonstrators set tyres alight, while several youths were arrested at one of the venues for the demonstrations in the capital.
Opposition leader Raila Odinga, who narrowly lost last year's presidential election to William Ruto, has vowed that the rallies go ahead.
Kenyans are suffering from surging prices for basic necessities, as well as a sharp drop in the local shilling against the US dollar and a punishing drought that has left millions hungry.
Nairobi police chief Adamson Bungei said on Sunday that police received requests to hold two demonstrations only late on Saturday, when normally three days' notice is required for public rallies.