In its quarterly update for January to March published on Tuesday, - the U.N. said violence was "becoming more extreme and more frequent (and) spreading relentlessly as gangs seek to extend their control."
"Every report I get from Haiti underlines the scale of the suffering and rams home the message that Haitians need urgent support and they need it now," said the U.N. High Commissioner for Human Rights, Volker Turk.
"In the month of April alone, more than 600 people were killed in a new wave of extreme violence that hit several districts across the capital," Turk's office said, adding that areas previously considered safe were now affected.
"This follows the killing of at least 846 people in the first three months of 2023, in addition to 393 injured and 395 kidnapped during that period - a 28-percent increase in violence on the previous quarter."
He repeated his call for the international community to send a specialized armed force to help Haiti's police and authorities restore order.
The Caribbean nation, the poorest in the Americas, has been gripped by a political and economic crisis since the assassination in July 2021 of president Jovenel Moise.
Rival gangs now control most of the capital, Port-au-Prince.
The report said gangs were using snipers to shoot "indiscriminately" at people on the street and "firing into homes," and people were "being burned alive on public transport."
Turk said the Haitian state did "not have the capacity to respond," so civilians were forming vigilante groups to fight the gangs.
This had led to a rise in "mob killings and lynchings of alleged gang members." At least 164 such murders were documented in April alone.
"This will only fuel the spiral of violence," said Turk, who last week warned that Haiti was "dangling over an abyss."
"We must not forget that extreme poverty and the lack of basic services lie at the root of the current violence and of the gangs' power over communities," he said.
"The government, with support from the international community, must do its utmost to comply with its obligation to provide people with regular and unimpeded access to clean water, food, health and shelter," Turk added.
