A steady stream of illegal weapons smuggled into Haiti is fueling an increase in gang violence and leading to severe human rights abuses, according to a U.N. report released Thursday.

More than 4,200 people were killed from July to February, and another 1,356 were injured, the report found. It was issued after William O’Neill, the U.N. human rights commissioner’s expert on Haiti, recently visited the troubled Caribbean country.

While much of the violence has been unleashed by gangs who…