The Honduran government is in talks to resolve the impasse created by a June 28 military coup that ousted President Manuel Zelaya, who has returned to Honduras and taken refuge in the Brazilian Embassy.
"This action is a reflection of the seriousness and urgency with which the U.S. government takes the need for the de facto regime to reach an agreement with President Zelaya to restore the democratic order," Luoma-Overstreet said.
The United States, which has condemned Central America's first coup in more than a decade, revoked a number of diplomatic and official visas after Zelaya's ouster on charges he violated the Honduran constitution by seeking to allow presidential re-election.
Later revocations included tourist visas for others linked to the de facto government. Luoma-Overstreet would not say how many visas were canceled in the latest round on Monday.
Talks to resolve the crisis in Honduras have sputtered with both sides stuck on the question of whether Zelaya can return to the presidency before a November election.
Honduras is President Barack Obama's biggest challenge in Latin America and some critics say the United States is not doing enough. Human rights groups accuse the de facto rulers of major abuses, including deaths, and say a free and fair election would be impossible unless Zelaya is reinstated first.
Zelaya, a logging magnate who became an ally of leftist Venezuelan President Hugo Chavez while in office, has been camped out with his family and supporters at the Brazilian Embassy since sneaking back into the country last month.
The army blasted the embassy with loud recordings of rock music, army marching tunes, pig grunts and church bells for six hours beginning shortly after midnight on Wednesday, said a Reuters witness inside the compound.
"(There is) worry about the increase in hostilities toward the Brazilian embassy in Tegucigalpa which have intensified in recent days particularly during the night," said a statement from the head of the Organization of American States.
Zelaya is calling on the OAS to condemn de facto leader Roberto Micheletti, who was installed by Congress after the coup, accusing him of deliberately obstructing the negotiations.