By LYDIA POLGREEN
 
PORT-AU-PRINCE, Haiti, March 10 — Gérard Latortue, the economist and former diplomat chosen by a United States-backed council to lead Haiti out of its political crisis, arrived in the country from southern Florida on Wednesday, promising to reconcile opposed factions and bring peace and prosperity to a nation long wracked by poverty and brutalized by generations of dictators.

"I come with all my impartiality, with no political party," Mr. Latortue said at a hotel in Port-au-Prince. "I come to work with all Haitians."

The arrival of Mr. Latortue, the country's new interim prime minister, was the clearest sign yet that a new Haitian government was beginning to take shape as the nation continued to struggle to right itself after the departure of Jean-Bertrand Aristide, Haiti's first democratically elected president. With armed rebels menacing the capital and with the United States and other nations pressuring him to step down, Mr. Aristide fled into exile in Africa on Feb. 29.

Mr. Latortue said he would appoint Herard Abraham, a former general who has wide support and was one of three top candidates to be prime minister, as the head of the nation's security, a move likely to placate armed rebels, many of whom were members of the Haitian Army before it was disbanded by Mr. Aristide.

Mr. Latortue fled Haiti in the late 1960's, when he faced political persecution from the Duvalier regime, and he returned only for brief spells. During one, in 1988, he served as foreign minister in the civilian government of Leslie Manigat, whose administration was ended by a coup after just four months. He worked for a United Nations agency for decades and is a business consultant.

He replaces Yvon Neptune, a stalwart of Mr. Aristide's Lavalas Party who stayed on after Mr. Aristide fled to help smooth the transition to a new government. Under Haiti's Constitution, the prime minister is in charge of running the government, but under Mr. Aristide, virtually all authority rested in the president's National Palace.

The interim president, Boniface Alexandre, a justice on Haiti's Supreme Court, will serve in a largely symbolic role.

Mr. Latortue's arrival drew mixed responses across the city. Leslie Voltaire, a close adviser to Mr. Aristide and a top government minister, said that Mr. Latortue's reputation — for honesty and technocratic skills — was beyond reproach.

"He is neutral and independent," Mr. Voltaire said. "He has no political constituency. He is not going to have a vested interest in any party."

A spokesman for the political opposition to Mr. Aristide, Micha Gaillard, called Mr. Latortue "a real professional and a man of integrity" but said he had lived outside of Haiti for too long.

In La Saline, a vast slum in the capital and a stronghold of support for Mr. Aristide, Mr. Latortue's name barely registered.

"We don't know who he is," said Ernseau Bolivar, a student. "We want Aristide back."

On Wednesday, American marines shot and killed two Haitian men who had fired at them from atop a building near the prime minister's house, said a military spokesman, Maj. Richard A. Crusan. That brought the total number of Haitians killed since foreign troops arrived here Feb. 29 to four.