Doctors Without Borders said on Tuesday that it is stopping operations across the Haitian capital, Port-au-Prince, and its wider metropolitan area because of an escalation in violence and threats to its staff from members of the Haitian police.
The suspension would begin Wednesday and last "until further notice," Doctors Without Borders — also known as MSF — said.
MSF said in a statement that since a deadly attack on one of its ambulances last week, police had repeatedly stopped its vehicles and directly threatened their staff, some with death or rape.
"We are used to working in conditions of extreme insecurity in Haiti and elsewhere, but when even law enforcement becomes a direct threat, we have no choice but to suspend our projects," MSF's Haiti mission chief Christophe Garnier said.
A spokesperson for Haiti's national police declined to comment.
Earlier Tuesday, police reported that more than two dozen suspected gang members were killed after residents joined police to fight off attempted overnight attacks in a resurgence of a civilian vigilante movement.
MSF, whose presence grew in Haiti in the wake of the devastating 2010 earthquake, is one of the main providers of quality free health care in the Caribbean nation and operates key services such as a trauma center and a burn clinic.
The United Nations estimated last month that 24% of the Port-au-Prince metropolitan area's health facilities remain open, while those outside the capital face an influx of displaced people jeopardizing their ability to provide essential care.
MSF cited four separate incidents of police threats and aggressions, including from an armed plain clothed officer it said threatened to start executing and burning staff, patients and ambulances as of next week.
Each week, the medical aid group treats on average 1,100 outpatients, 54 children in emergency situations, more than 80 sexual- and gender-based violence survivors, and many burn victims, MSF said.
Garnier added that while MSF remained committed to the population it could only resume services if it receives guarantees of security and respect by armed groups, members of self-defense groups and law enforcement.
In the earlier violence, residents joined police to fight off an attempted overnight attack on an affluent hillside suburb of Port-au-Prince, police said.
The suburb of Petion-Ville was closed off on Tuesday as residents barricaded streets and asked those not from the area to stay home as they mobilized, some with machetes and hammers in hand, to protect the district from another gang invasion.
A Reuters reporter saw at least 25 bodies across the neighborhoods of Petion-Ville, Delmas and Canape Vert.
National police deputy spokesperson Lionel Lazarre told Reuters about 30 people he described as gang members had been fatally wounded throughout the day.
"The population stood along the Haitian National Police during these moments. They will continue to work hand in hand," he said.
The U.N. has reported at least 149 cases of vigilantism between June and September this year, just more than half outside Port-au-Prince where residents fear gangs spreading their influence from the capital.
The U.N. Security Council approved a support mission last October but has so far deployed just a fraction of the promised personnel. Haitian leaders have pushed for it to be transformed into a peacekeeping mission to secure more funding.