PORT-AU-PRINCE, Haiti — A day after Haiti's runoff election for president, the candidates kept a low profile Monday while they and the voters were left to wait at least a week and a half for official results.

The scene in Port-au-Prince was calm, as it had been Sunday during balloting in the race between popular singer Michel Martelly and university administrator Mirlande Manigat. Preliminary results are due March 31.

A final tally is to be announced April 16, almost a month after the balloting, to give the candidates a chance to lodge legal challenges.

Haitian officials and foreign observers said that even though some polling places opened late or without ballots or ink, Sunday's vote was smoother than the chaotic first round of voting on Nov. 28, when many voters were unable to cast ballots due to organizational lapses.

The first-round vote was also marred by allegations of vote-rigging by the ruling party, which was eventually denied a spot in the runoff.

Since then, Haitian election officials, aided by foreign diplomats, scrambled to repair flaws in the voting system and to hire and train hundreds of new poll workers. Haiti's election commission employed a 24-hour telephone hot line and text messages to guide voters to the right polling places.

"It was a much smoother election day than the 28th," said Jon E. Piechowski, a spokesman at the U.S. Embassy, which denounced "inconsistencies" when early results were announced last time. "The Haitian voters arrived at the voting centers much better prepared."

The United Nations called the vote a step forward for Haitian democracy and urged the two camps to be patient during the wait for results. In a statement, the UN peacekeeping mission said the "future of the country is at stake."

The return of former President Jean-Bertrand Aristide before the vote appeared to have little effect on voting, despite worries of intensified tensions.

Aristide, who arrived Friday after seven years of exile in South Africa, criticized the exclusion of his leftist party, Fanmi Lavalas, from the presidential election. Voting was calm, though, in the sprawling Cite Soleil slum, an Aristide stronghold.

Nor did it seem to matter much that former dictator Jean-Claude Duvalier was back after 25 years in exile. He returned in January but has kept a fairly low profile.

Some who voted were on guard for possible trouble later.

"If there's any problem, it's going to be afterward, in the counting," 31-year-old Jerome Gaspar said after voting in a Cite Soleil school. "But we did our job by voting."