"In the meeting with the vice president of the United States, they were insistent on the safe third country issue", Ebrard told a press conference, three days after reaching a last minute deal to avoid punitive tariffs over the surge of Central American migrants arriving at the US-Mexican border.
President Donald Trump talks with reporters before departing on Marine One for the Air Force Academy graduation ceremony.
But he could be alluding to the idea of Mexico becoming a "safe third country", which would make it harder for asylum seekers who pass through the country from other places to claim refuge in the U.S. The official spoke on condition of anonymity to share details of closed-door talks.
Trump said that if his predecessor, Barack Obama, made the deal he made with Mexico, the media would declare a "National Holiday" in his honor. In retaliation, China also hiked tariffs on $60 billion worth of United States imports from June 1.
His apparent victory, more illusory than real because it comprised elements Mexico agreed to months ago, further alienated important business groups, antagonized his putative allies on Capitol Hill and deepened suspicions across North America, where the revision of NAFTA remains a raw issue even as congressional approval of the new pact remains uncertain.
"It's hard to say [what the last term of the agreement is], because both the US government and the Mexican government have been very vague about the sort of secondary agreement that happened", says Pierce.
"I want to be quite clear - there is no agreement of any kind that has not been made known", Ebrard said on Monday. "But that is what there is here".
The United States, making official a policy that has triggered opposition in both countries, said it would systematically send back asylum seekers who cross the border, pending a decision on their claims.
He did not clarify what that might look like.
The U.S. -Mexico Joint Declaration released this Friday by the State Department also mentioned no such information, which Trump said that the agricultural deal was included in.
Mexico said it would deploy its National Guard throughout the country from Monday with 6,000 additional troops being sent to its southern border with Guatemala.
There was no specific migration reduction target, Ebrard said, noting that when he began talks in Washington last week to defuse the tariff threat, the US government wanted Mexico to accept a "safe third country" agreement over migration.
The officials did not say whether US authorities had already requested the programme be extended to particular cities.
"I think the president has completely overblown what he purports to have achieved", Beto O'Rourke, a presidential contender, told ABC on Sunday.
"And as with so many other occasions, our stories stand up over time and the president's denials of them do not".
Secretary of State Mike Pompeo said Monday that the USA and Mexico will know within 45 days whether the new border security deal the two countries hashed out is working. Without the threat, he has insisted, Mexico never would have acted.
Versa reported from Mexico City.