Haiti's success depends on whether its people can unite behind a new government, a top U.S. diplomat said Monday, calling ousted President Jean-Bertrand Aristide's possible return "one of the least important questions" facing the country.

Thomas Shannon, assistant U.S. secretary of state for Western Hemisphere affairs, urged Haitians to support president-elect Rene Preval's government and to help the impoverished nation "meet the tremendous development challenges that it faces."

"The success or failure of Haiti will depend on whether or not the Haitian government and the Haitian people work together," Shannon told reporters during a one-day visit to meet with Preval and Haitian officials.

Shannon's visit came more than a week after Preval was declared the winner of Feb. 7 elections, the first since a revolt two years ago toppled Aristide, a former ally of Preval who still enjoys wide support among Haiti's poor.

Aristide has been living in exile in South Africa, and Preval has said Aristide's return is permitted under the constitution.

But Shannon downplayed that possibility when asked how the United States would react.

"From our point of view, it's one of the least important questions that Haiti faces at this time," Shannon said. "We are focused on Haiti's future, not on its past, and we believe the Haitian people are also."

Shannon said he didn't believe Haitians would take to the streets calling for Aristide's return. "Mr. Aristide has been gone for over two years, and those protests haven't appeared," he said.