The US and other nations in the region have welcomed Thursday's proclamation of Rene Preval as president of Haiti.
Jubilant crowds celebrated Rene Preval's victory
Washington said it would see what it could do to help Haiti, a country plagued by instability and poverty.
The 7 February vote was marred by fraud claims, which led to days of protests demanding Mr Preval be declared winner.
He gained 51% of the vote after a change in the way blank ballots were allocated. Runner-up Leslie Manigat accused officials of staging a coup.
He called the deal "the imposition of a victor" and said it was "a reward for violence".
But UN Secretary General Kofi Annan described the deal as a "reasonable way to attempt to resolve a conflict, an impasse that could have led to conflict and violence".
US Secretary of State Condoleezza Rice said Mr Preval's proclamation gave Haiti a new chance.
Brazil and Chile - the two Latin American countries leading the UN mission in Haiti - also welcomed the election of a new president. Both countries warned that the international community had to continue to provide assistance.
Brazil is hosting a meeting next week about how to speed up donations to Haiti, the poorest country in the Americas.
In the Haitian capital, Port-au-Prince, jubilant crowds poured into the streets on Thursday to celebrate Mr Preval's victory.
UN peacekeepers are reported to have stepped up security to prevent any rioting by his opponents.
Thursday's agreement followed days of demonstrations, fuelled by the apparent discovery of charred ballot papers at a dump near Port-au-Prince.
Rene Preval has support among the country's poor
Mr Preval had warned of more protests if partial results - which suggested he was just short of the 50% needed to win outright - were published as final.
The candidate of the small L'Espwa (The Hope) party, Mr Preval was once an ally of ousted former President Jean-Bertrand Aristide and has inherited his following among the poor.
An agronomist who studied in Belgium, Mr Preval was active in the movement to oust military ruler Jean-Claude "Baby Doc" Duvalier during the 1970s.
Mr Preval was prime minister for a brief period in Mr Aristide's first administration in the early 1990s.
He replaced Mr Aristide as president between 1996 and 2001.