Manuel Zelaya was sent into exile following June's army-backed coup
The interim government of Honduras has ordered all Argentine diplomats to leave the country within three days.
It said the move was in response to the expulsion of its ambassador last week by Buenos Aires, one of the strongest critics of June's military-backed coup.
The Honduran ambassador was told to go because of her public support for the overthrow of President Manuel Zelaya.
In a separate development, US officials held talks in Washington with a delegation from the interim government.
The meeting, held at the headquarters of the Organisation of American States (OAS), was aimed at working "toward restoration of democratic and constitutional power in Honduras", State Department spokesman Ian Kelly said.
Mr Zelaya was ousted and exiled amid a power struggle over his proposals for a public consultation on constitutional change.
His critics said the move was aimed at removing the current one-term limit on serving as president and paving the way for his re-election.
After Mr Zelaya's removal Congress Speaker Roberto Micheletti, constitutionally second in line to the presidency, was sworn in as interim leader.
US Secretary of State Hillary Clinton said the US, which supports Mr Zelaya's return to office, continued "to believe in the need for a negotiated solution" to the crisis.
For the second time since 28 June, Mr Micheletti's government ordered the expulsion of foreign diplomats in a row over the ousting of Mr Zelaya.
Venezuela's envoys have also been told to leave but have so far refused, saying they will not recognise an order by the country's interim leadership.
The latest order came five days after Argentina expelled the Honduran ambassador, Carmen Eleonora Ortez Williams, at Mr Zelaya's request.
The Honduran foreign ministry said the decision was made on the basis of "strict reciprocity".
Diplomatic relations will now pass through the Israeli embassy.
Buenos Aires supports the position of the OAS, which has condemned Mr Zelaya's removal and demanded his reinstatement.
A visit by an OAS delegation of six foreign ministers was postponed last week after the interim government said it did not want the group's secretary-general, Jose Miguel Insulza, to accompany them, saying he lacked objectivity.
Meanwhile, a delegation from the Inter-American Commission on Human Rights is currently in Honduras to investigate reports of repression against Mr Zelaya's supporters following the coup.