Argentina and Ecuador expelled their respective ambassadors over a dispute over a former Ecuadorian official.
Former public works minister María de los Ángeles Duarte had been staying at the Argentine embassy in Quito for more than two years.
But at the weekend she left Ecuador and traveled to Venezuela, where she requested asylum in the Argentine embassy in Caracas.
The Ecuadorian government condemned the unauthorized departure, and blamed Argentine ambassador Gabriel Fuks, whom it ordered to leave the country after declaring him "persona non grata".
In response, the Argentine authorities took the same decision with Ecuadorian Ambassador in Buenos Aires, Xavier Monge Yoder.
Duarte was part of the government of former president Rafael Correa and was convicted of corruption.
But both Correa and Duarte see the legal cases against them as part of a political persecution.
Last December, the government of President Alberto Fernández asked Ecuador for safe conduct so that Duarte could travel to Argentina.
But Guillermo Lasso's government rejected the request, which led Duarte to leave the country incognito, she revealed on Twitter.