The gun trafficking, including even heavy machine guns, is "fuelling an ongoing surge of gang violence that has plagued residents for months," said the United Nations Office on Drugs and Crime (UNODC).

Haiti -- the poorest country in the western hemisphere -- has been mired for years in a vicious cycle of humanitarian, economic and political crises exacerbated by brutal gang violence.

"The incidence of homicides, kidnappings, and displacement is rising across Haiti, which is suffering the worst human rights and humanitarian emergency in decades," the report said.

Authorities reported 2,183 homicides and 1,359 kidnappings in 2022 -- almost double the cases for the previous year.

Gangs control more than half the country, the study notes.

The UNODC based its findings on "a recent increase in arms seizures alongside intelligence and law enforcement reporting".

The study "seeks to shed light on the trafficking flows enabling gangs in Haiti... and (the) desperate situation, to help inform responses and support to the people of Haiti," said Angela Me, chief of the Vienna-based UNODC Research and Trend Analysis Branch.

Most of the firearms come from the United States and transit via Florida, where Haitian exiles often use containers carrying ordinary goods to conceal the guns.

Hand guns costing under $500 in the United States can be sold for as much as $10,000 in Haiti, where gang members have a preference for rifles including AK47s, AR15s and Galils.

"Haiti's porous borders are severely challenging the capacities of the under-resourced and under-staffed national police, customs, border patrols and coast guard, who are themselves targeted by gangs," UNODC said.

Canada has deployed two warships off Haiti to conduct surveillance and support local police efforts to control gangs.