There have been scenes of chaos and confusion in Haiti after several presidential candidates called for Sunday’s vote to be cancelled.
Twelve of the 18 people contesting the ravaged nation’s top job have alleged widespread fraud.
They include the prominent front runner, Mirlande Manigat.
The former first lady and her 11 colleagues have accused outgoing President Rene Preval’s unity coalition of trying to steal the elections.
Voters at one polling station trashed the centre, shouting “thief thief”. Violence spilled over into the street.
The criticism of the election is a blow to the credibility of the UN-supported poll. The international community was hoping they could produce a stable, legitimate government after Haiti was devastated by January’s earthquake and continues to struggle with a cholera epidemic.