The prospect of a second, run-off round in Haiti's presidential election grew as the results after two-thirds of the votes had been counted were announced.
Rene Preval has strong support among Haiti's poor
Former President Rene Preval, a one-time ally of ousted leader Jean-Bertrand Aristide, saw his share of the vote drop to 49.6%.
Mr Preval needs at least 50% to avoid a run-off round, and final results are expected on Sunday.
Supporters marched in Port-au-Prince on Saturday, insisting he had won.
Some have also alleged fraud, although international observers say the process has been free and fair.
With 72% of the vote counted, another ex-leader, Leslie Manigat's has 11.6% of the vote, while industrialist Charles Henry Baker has 8.1%, electional officials say.
Mr Preval held 61% of the vote after the first results were released on Thursday, but the figure had dropped to 50.2% on Friday.
The country - the poorest in the Americas - is choosing a 129-member parliament as well as a new president.
While the election process has been considered peaceful, correspondents say there are fears that a possible second round may bring fresh instability.
Several hundred people marched on the National Palace in the capital on Saturday in support of Mr Preval, who has inherited Mr Aristide's strong support among Haiti's poor.
"If they don't give us Preval, there will be no peace," a 46-year-old woman, who called herself Marie, was quoted by Reuters news agency as saying.
"Somebody paid the election council to give away the result."
Warning over Aristide
Charles Henry Baker has also alleged fraud, claiming some people were allowed to vote more than once because voter lists were not followed.
International observers say there have been some minor procedural irregularities but have deemed the election free and fair.
Haitians have had a long wait for a new elected president
The US State Department has also declared the voting process free from fraud.
"The key here is that there is a high turnout. The Haitian people invested in this election process," state department spokesman Sean McCormack said.
However, in an implicit warning to Mr Preval - who once had strong links with Mr Aristide - the spokesman said the US expects the deposed leader to remain in exile in South Africa.
Mr Preval has told the BBC Mr Aristide may return if he wishes, although he would not tolerate the violent groups that have pledged allegiance to him.
In one positive sign, a prominent gang leader declared that his group would lay down their guns if Mr Preval - seen as the champion of the poor - becomes president.