Brazil's foreign minister has urged the UN Security Council to address the growing unrest in Haiti, following last Tuesday's presidential elections.
Celso Amorim is said to have made the request during a phone call with US Secretary of State Condoleezza Rice.
At least one person has been killed and several injured in clashes in Haiti.
Supporters of front-runner Rene Preval have set up roadblocks in the capital, Port-au-Prince, and occupied a hotel, demanding he be declared the winner.
Witnesses said UN peacekeepers had opened fire on protesters, but the UN said its troops had fired in the air.
Mr Preval returned to Port-au-Prince on Monday as his share of the vote fell further, raising the prospect of a run-off, according to electoral officials.
With nearly 90% of the ballots counted, the former president has 48.7% of the vote - just short of the 50% required to win outright.
Mr Preval used to be an ally of former President Jean-Bertrand Aristide, who was forced out of power in 2004. He has inherited Mr Aristide's strong support among the poor.
Another ex-leader, Leslie Manigat, has 11.8%, while industrialist Charles Henri Baker has 7.9%, officials say.
After making his request for a UN Security Council meeting, Mr Amorim described the situation in Haiti as worrying.
Mr Amorim, whose country heads a contingent of 9,500 UN troops in Haiti, said the international community needs to act with firmness and prudence.
The US is presiding in the UN Security Council in February and so sets its agenda.
On Monday, thousands marched in Port-au-Prince for a second day as it became increasingly apparent that Mr Preval might face a run-off on 19 March.
Angry protesters say electoral officials have tampered with the vote count to keep him from a first-round victory.
Final results had initially been scheduled for Sunday evening - but as it stands now they may not be known for a few days.
Burning tyres and roadblocks paralysed the capital's streets.
Witnesses told local media that UN peacekeepers had fired into crowds of demonstrators massing in the middle class Tabarre district, killing at least one.
But UN spokesman David Wimhurst insisted troops had only fired two shots in the air. "No individuals were wounded by UN peacekeepers," he said.
'Free and fair'
In the Petionville neighbourhood, thousands of screaming Preval supporters poured into the luxury Montana Hotel, where election officials have been tallying results.
UN peacekeepers barred access to the election centre and - after hours spent chanting pro-Preval slogans and frolicking in the hotel pool - the crowd finally dispersed.
Mr Preval, who is leading more than 30 presidential candidates, held a 61% lead when the first results were released late last week, but his share of the vote has since dropped.
There have been accusations of ballot mishandling - but the head of Haiti's electoral council has denied the allegations.
International observers have deemed the election free and fair, despite saying there were some minor procedural irregularities.
Haiti - the poorest country in the continent - is choosing a 129-member parliament as well as a new president.