Health workers have tried to stop the unrest, but Haitians have ignored the exhortations to keep the peace. The violence, which has spread to Port-au-Prince, has disrupted treatment efforts.
The outbreak has killed more than 1,100 people and affected more than 16,000 others. The violence comes as the nation prepares for elections on Nov. 28.
U.N. officials argue that the violence is being encouraged by forces that want to disrupt the ballot, and some demonstrators Thursday threw rocks at an office of President Rene Preval's Unity party and tore down campaign posters.
But the anger is fueled by suspicions that a contingent of Nepalese soldiers brought cholera with them to Haiti and spread the disease from their rural base into the Artibonite River system, where the initial outbreak was centered last month. It is a suspicion shared by some prominent global health experts.
The epidemic has also spread to the Dominican Republic, where a Haitian construction worker was reportedly hospitalized this week with cholera.
Dominican health officials were also reportedly investigating a possible second case, this one also involving a Haitian resident who was hospitalized.
Health authorities launched a nationwide search Thursday for people suffering from symptoms typical of cholera: diarrhea, vomiting and dehydration.
Health Minister Bautista Rojas said hundreds of doctors, epidemiologists and other medical officials will be going "house by house, in each sector, neighborhood and alleyway," looking for any trace of an outbreak.
They will interview neighbors, offer medical care and, if necessary, take anyone suspected of having cholera to the hospital.
The Dominican Republic has stepped up health measures to try to keep the epidemic from crossing the border — especially after the nation's first cholera case was detected Monday in an immigrant brick worker who returned sick after a vacation in his Haitian homeland.
Dominican authorities have increased border patrols and monitoring of frontier crossings. The two nations share the Caribbean island of Hispaniola.
The disease has also made its way to Florida, and nearby Puerto Rico has warned its residents to avoid traveling to countries where the epidemic has taken hold.
Cholera had not been recorded before in Haiti despite rampant bad sanitation and poor access to drinking water, problems that cause outbreaks of the disease in other parts of the world. Cholera is endemic to Nepal and there was an upsurge there before the Nepalese troops came to Haiti.
Experts have not pinpointed the origin of Haiti's epidemic, however, and the 12,000-member U.N. Stabilization Mission in Haiti, or MINUSTAH, denies responsibility.
U.N. peacekeepers have been the dominant security force in Haiti for six years, and there was resentment against them even before the cholera outbreak.
Standing before the thick black smoke of blazing tires Thursday, protesters in Port-au-Prince yelled "We say no to MINUSTAH and no to cholera." Some carried signs reading
"MINUSTAH and cholera are twins." The windows of several cars belonging to the United Nations and to humanitarian groups were broken.
"It's not only that (the U.N. peacekeepers) have to leave but the cholera victims must get paid (damages)," said Josue Meriliez, one of the demonstrators.
Haitian police fired tear gas at the protesters on the central Champ de Mars plaza, and clouds of choking irritants blew into nearby tent shelters of thousands made homeless by the Jan. 12 earthquake.
Protesters also threw rocks at a motorcade leaving the national palace, which fired warning shots to clear a path. It was not immediately known if President Rene Preval was in the motorcade.
Aid workers, including U.N. humanitarian agencies that are structurally separate from the peacekeeping force, have been calling for calm, saying the violence is hampering efforts to treat the tens of thousands of people stricken with cholera.
The disease is spread by contaminated fecal matter. Health experts say it can be easily treated with rehydration or prevented outright by ensuring good sanitation and getting people to drink only purified water.
But after years of instability, and despite decades of development projects, many Haitians have little access to clean water, toilets or health care.
The Associated Press contributed to this story. AP writers Evens Sanon in Port-au-Prince and Ezequiel Abiu López in Santo Domingo, Dominican Republic, reported.