Police shot volleys of tear gas at hundreds of protesting youths chanting slogans against President Uhuru Kenyatta in Kenya's western city of Kisumu on Monday, a Reuters witness said. "Uhuru must go," groups of youths chanted in Kisumu, as well as shouting slogans in support of opposition leader Raila Odinga, who has called for a mass rally in the capital to demand dialogue with the government over a range of grievances. The Reuters witness reported that two groups of protesters, each group of 200 or more youths, had tried to march to the centre of the city but were held back when dozens of police fired tear gas. Police also fired tear gas at some protesters in Nairobi.