Gang violence killed or injured at least 234 people from July 8-12 in Haiti's Cite Soleil, an impoverished and densely populated neighborhood of the capital Port-au-Prince, the United Nations said on Saturday.
The unrest erupted between two rival factions, and the city's ill-equipped and understaffed police failed to intervene, trapping residents in their homes, unable to go out even for food and water.
With many houses in the slums made of sheet metal, residents fell victim to stray bullets. Ambulances were unable to reach those in need.
"Most of the victims were not directly involved in gangs and were directly targeted by gang elements. We have also received new reports of sexual violence," said U.N. human rights office spokesperson Jeremy Laurence.
Earlier this week, the National Human Rights Defense Network, a Haitian organization, had put the toll at 89 people killed, 16 unaccounted for and 74 wounded.
For the six months from January to June, the U.N. human rights office put the death toll at 934, with 684 more people wounded. A total of 680 kidnappings also occurred during that period, it said.
"We are deeply concerned by the worsening of violence in Port-au-Prince and the rise in human rights abuses committed by heavily armed gangs against the local population," Laurence said.
"We urge the authorities to ensure that all human rights are protected and placed at the front and center of their responses to the crisis."
The bloodshed in Haiti has come alongside soaring food prices and chronic fuel shortages, a toxic mix that has accelerated a brutal downward spiral in the security situation in Port-au-Prince.
Aid agencies say many areas are impossible to access because of the dangerous conditions.
"We call on those responsible and supporting this armed violence to immediately desist, and to respect the lives and livelihoods of all Haitians, most of whom live in extreme poverty," Laurence said.
Mumuza Muhindo, head of the local mission of Doctors Without Borders, told AFP that his group had operated on an average of 15 patients a day during the spike in violence.
"It's a real battlefield," Muhindo said. "It's impossible to estimate how many people have been killed."
Cite Soleil is home to an oil terminal that supplies the capital and all of northern Haiti, so the clashes have had a devastating effect on the region's economy and people's daily lives.
Gas stations in Port-au-Prince have no fuel to sell, causing prices on the black market to skyrocket.
"We are seeing a significant increase in hunger in the capital and in the south of the country, with Port-au-Prince hit the hardest," Jean-Martin Bauer, director of the World Food Program, said on Tuesday.
For the past several years, Haiti has seen a wave of mass kidnappings, as gangs snatch people of all walks of life, including foreigners, off the streets.
Emboldened by police inaction, gangs have become increasingly brazen.
Haiti announced a rare seizure of weapons in cargo containers late Thursday: 18 military grade weapons, four 9 mm handguns, 14,646 rounds of ammunition and $50,000 in counterfeit money.
The following day, the U.N. Security Council called on member states to ban the transfer of small arms to the Caribbean nation but stopped short of a full embargo requested by China.
