In a television interview Monday, Mr. Zelaya said he had returned to Honduras to reclaim his presidency in accordance with the will of the people. He called for for a national dialogue.
Initial reports that Mr. Zelaya had returned were unclear about his exact location. Crowds of supporters rallied outside the United Nations building in Tegucigalpa amid reports that he was inside.
A spokesman for the U.S. State Department, Ian Kelly, said the U.S. reiterates its "almost daily" call for supporters of both Mr. Zelaya and interim President Roberto Micheletti to exercise restraint and refrain from actions that could provoke violence.
Kelly added the U.S. still considers Mr. Zeyala Honduras's democratically elected and constitutional leader.
Mr. Zelaya was forced out of the country at gunpoint on June 28. Leaders of the interim government that ousted him in the military coup have said he would be arrested if he returns.
The United States has refused to recognize President Micheletti's interim government despite that government's assertion Mr. Zelaya was legally removed. The interim leaders say Mr. Zelaya violated a Supreme Court order to drop efforts to change the constitution.