Demanding the annulment of elections in Haiti.
For the second time in three days hundreds of protesters have clashed with riot police.
Results of parliamentary and presidential polls are due to be released on Tuesday.
But the country’s Provisional Electoral Council is under pressure over claims of fraud.
There are also complaints the country was not ready for a ballot, as it struggles to recover from a deadly earthquake in January.
Opposition candidate Fleurissant Junior Raymond said: “The aim of this demonstration is to ask for the annulment of this electoral deception that took place on November 28. We’re simply asking for a change to the electoral council, which is getting us nowhere.”
The UN mission in Haiti and overseas observers have cautiously endorsed the elections and called on all sides to accept the results.