"We have said again and again that we are not ready to sign" any agreement of this kind, she said at an event in Washington, D.C.
This recognition occurs a few days before July 22, the deadline for the U.S.-Mexico agreement which allowed the Latin American country to avoid the President Donald Trump's economic sanctions in exchange for committing itself to halt the flow of Central American migrants to the U.S. Southern border.
According to the June bilateral agreement, whose full details have not been disclosed thus far, if Mexico fails to fulfill its survaillance mission, it will have to accept the status of a safe third country.
The Mexican ambassador's comments also comes before Mexico's Foreign Affairs Minister Marcelo Ebrard meets U.S. Secretary of StateMike Pompeo to discuss migration-related issues in Mexico City this weekend.
On July 15, the Trump administration announced new rules that prohibit almost all immigrants from applying for asylum on the U.S.-Mexico border. The immigrants will be asked to request asylum in a country which they have passed though on their trip to the U.S.
In this regard, Ambassador Barcena said that her government interprets that the new rules do not send migrants to Mexico but to their countries of origin.
According to international law experts, however, there are several difficult problems to solve in order to apply the the 'safe third country rule'.
"Whether a country can be considered safe for a given person requires an individualized determination. The asylum seeker must also have a meaningful connection to the third country that makes staying there reasonable, not just pass through it. The new regulation ignores these limitations," Fatma Marouf, the director of Immigrant Rights Clinic at Texas, wrote on an opinion article published by The Hill.