Police say six people have died and at least five were wounded during demonstrations across Haiti protesting allegations of embezzlement from a Venezuelan programme that provided the country with subsidised oil.
President Jovenel Moise called for dialogue with opposition groups that are seeking his resignation for failing to investigate corruption.
Thousands of Haitians marched Sunday to the National Palace in the capital, calling for a probe into the spending of $3.8bn Haiti received as part of the regional Petrocaribe programme.
Clashes with police erupted after protesters blocked streets and set fire to tires.
A Haitian Senate investigation has alleged embezzlement by at least 14 former officials in former president Michel Martelly's administration, but no one has been charged. There were reports of clashes in smaller protests across the country.