Florida health officials, meanwhile, confirmed a case of cholera in a woman who had visited Haiti, though they said the disease is unlikely to spread in the United States.
Riots began Monday in northern and central Haiti over suspicions that a month-old cholera epidemic that has killed more than 1,000 people was brought to Haiti by U.N. peacekeepers from Nepal.
The government sent senior officials to Cap-Haitien, Haiti's second-largest city, to quell the rioting in which at least two people died. President Rene Preval appealed for calm amid Tuesday fears that the unrest would spread to the capital ahead of the Nov. 28 presidential elections.
Wednesday's protests in Cap-Haitien were distinctly calmer, though flaming barricades remained and protesters threw rocks at police trying to remove them.
Anti-government demonstrators staged a small, relatively peaceful protest in Port-au-Prince on Wednesday, marching toward Haiti's collapsed national palace while tearing down and burning campaign posters of Jude Celestin - candidate of Preval's Unity party and head of the state-run construction company. Many of the protesters were recently laid off by the national telephone and construction companies.
Some chanted, "Unity equals cholera."
Aid workers said the rioting has interfered with efforts to combat the disease, which has officially hospitalized more than 16,700 people. The U.N. canceled flights carrying 3 metric tons of soap along with medical supplies and personnel because of violence in Haiti's north.
The violence against the U.N. peacekeepers combines widespread resentment against the foreign mission with suspicions about the recently arrived Nepalese soldiers, whose base had sanitation problems and was near the epicenter of the infection.
U.N. officials have declined to try to determine the source of the infection, but deny responsibility and say the protests are meant to disrupt the elections.
Amid concerns the infection could spread beyond Haiti's borders, the Florida Department of Health said Wednesday that a woman who had recently visited family in Haiti tested positive for cholera. She has since recovered.
The department said other suspected cases of cholera were under investigation in Florida, where there is a large Haitian diaspora community, but it said the disease is unlikely to spread because of better sanitation standards in the United States.
A Haitian man with cholera was also hospitalized in the eastern Dominican Republic, near the tourist centers of Punta Cana and Bavaro.
More Cholera Coverage
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"60 Minutes" | Frustration and Anger in Haiti
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Rush to Stop Cholera Spread in Haitian Capital