Two members of the Organization of American States have been kidnapped in the Haitian capital, police have said.
The poll is expected to be postponed again
The officials were working towards presidential elections, which were originally scheduled for 8 January but are now set to be delayed.
Electoral workers say conditions for holding the vote have not been met.
Haiti has been blighted by political and criminal violence since armed insurgents overthrew President Jean-Bertrand Aristide in 2004.
A UN peacekeeping force has been unable to restore complete order in the country.
The two OAS employees - a Guatemalan and a Peruvian - were abducted while driving on a road near the international airport.
The Haitian spouse of one of the two OAS workers was also abducted with them in Port-au-Prince, police said.
They were a short distance away from the Cite Soleil neighbourhood, where several kidnappings and shootings have taken place.
Officials in Haiti are widely expected to announce the postponement of elections scheduled for 8 January - the fourth such delay.
Electoral council official Pierre Richard Duchemin told the AFP news agency earlier this week: "We are not in a position to guarantee honest and credible elections can be held."
Haiti's interim leader Gerard Latortue has also urged officials to set a "more realistic" date for the vote.
Many of Haiti's electorate have yet to receive identification papers that will enable them to vote and the location of many polling stations has yet to be decided.
Meanwhile, violence has continued to rock the country, most of it linked to criminal and political rivalry between armed groups loyal to the exiled Mr Aristide or his successor.
A Canadian member of the UN's international peace-keeping force was shot dead in the street there last week.
On Thursday, police arrested 20 people suspected of taking part in kidnappings, in an operation which led to the release of two hostages.