Three civilians were killed and at least 20 injured in Kenya as supporters of the Opposition party clashed with the police as the country voted in the presidential election, the local Citizen TV reported on Thursday.

The police fired live rounds, tear gas and water cannons at stone-pelting youths who had come out in support of Opposition leader Raila Odinga’s call for a voter boycott. Riot police also fired tear gas shells in two slums in Nairobi. Protestors resorted to arson in the Kibera slum and firebombed a church in the Mathare slum.

The re-election was scheduled for Thursday after the Kenyan Supreme Court rejected the results of the August presidential election that declared incumbent Uhuru Kenyatta the winner. The top court said there were irregularities in the election proceedings and called for a fresh poll within 60 days.

The Opposition had urged voters to boycott the election rerun, which is likely to return Kenyatta to power as president. There were clashes between protestors and the police in several strongholds of the Kenyan Opposition.

Voting began at 6 am local time amid increased security. Earlier this month, Opposition leader Raila Odinga pulled out of the re-election, predicting it would be even worse than the first one.