A group of US missionaries and their family members, including children, are reported to have been kidnapped by an armed gang near Haiti's Port-au-Prince.
At least 15 people were taken off a bus after visiting an orphanage, Haitian security sources have told news media.
Few details are known, but US officials said they were aware of the reports.
Haiti has one of the highest rates of kidnapping in the world, as powerful gangs exploit the lawless situation to make money from ransom payments.
Since the killing of President Jovenel Moïse in July, rival factions have been trying to gain control and the lack of security has intensified the daily struggle to survive of many Haitians.
The Christian missionaries were seized shortly after leaving the town of Croix-des-Bouquets and continue to be held by the gang, according to a security source quoted by the AFP news agency.
The Haitian justice ministry and the National Police have not commented.
The US government is yet to provide any information on the incident, but the US state department told AFP it had seen the reports and that the safety of American citizens abroad was one of its highest priorities.
Christian Aid Ministries, a US-based organisation, sent a voice message to religious groups in Haiti as a "special prayer alert", the Associated Press news agency reported.
The message said the group was working with the US embassy in Haiti to "see what could be done" to help the abducted people.
Christian Aid Ministries supports Haitians largely through donations and supplies shelter, food and clothing to children and helps to fund their education.
Armed gangs have controlled the poorest districts of the Haitian capital for years. Recently they have extended their hold to other parts of Haiti's capital city Port-au-Prince and its outlying areas.
More than 600 kidnappings were recorded in the first three quarters of 2021, compared with 231 over the same period last year, according to a local civil society group.
Violence in Haiti - the poorest country in the Americas - has spiralled both since the assassination of President Moïse and an earthquake the following month which killed more than 2,000 people.
According to the New York Times, many in Haiti have been calling for the US to send troops to the country, a request the Biden administration is reluctant to accept.