Voting in one of Kenya’s largest slums was interrupted when protesters barricaded roads leading to polling stations as they engaged police with running battles on Thursday.
Police were forced to fire teargas to disperse the protesters in one of the opposition leaders' stronghold.
Kenya’s presidential election re-run is overshadowed by an opposition boycott that will almost certainly hand victory to President Uhuru Kenyatta, but with a mandate compromised by low turnout and procedural flaws.
Those shortcomings, already acknowledged by judges and the election commission, are likely to trigger legal challenges.