Peacekeepers shot one protester dead as riots blaming the United Nations for a cholera epidemic broke out in towns and cities across Haiti on Monday.
Ten civilians and six UN troops were injured in violence in Cap Haitien.
The soldiers had tried to use tear gas to disperse the protesters, who responded by throwing stones and barricading roads.
“There was a demonstrator who had a weapon and fired at a soldier, and the soldier returned fire in legitimate self-defense,” said Vicenzo Pugliese, a spokesman for the UN mission known by its initials MINUSTAH.
Pugliese said the violence was politically motivated ahead of presidential and parliamentary elections on November 28.
The protesters accuse Nepalese blue helmets of bringing the bacteria behind the deadly outbreak into the country.
Their base is close to the river where the first cases were recorded.
Cholera is a waterborne disease that can cause diarrhoea and vomiting, leading to severe dehydration and potentially death.
The epidemic has killed more than 900 people and sickened as many as 15,000.