STERLING, Va. — Three days after U.S. President Donald Trump announced a deal with Mexico to stem the flow of migrants at the southern border, the two countries appear unable to agree on exactly what’s in it.

Stung by criticism that the agreement mostly ramps up border protection efforts already underway, Trump on Monday hinted at other, secret agreements he says will soon be revealed.

“We have fully signed and documented another very important part of the Immigration and Security deal with Mexico, one that the U.S. has been asking about getting for many years,” Trump wrote Monday, saying it would “be revealed in the not too distant future.”

Not so, said Mexican Foreign Secretary Marcelo Ebrard, holding up a paper and pointing to the previously announced details. He told reporters the two countries agreed on two actions made public Friday and said if those measures didn’t work to slow migration, they would discuss further options.

“There is no other thing beyond what I have just explained,” he said.

The episode revealed the complicated political dynamics at play as Trump and Mexican President Andrés Manuel López Obrador tussle over who made out best in the agreement hashed out under Trump’s threat of new tariffs on Mexico. Trump appeared eager to declare his negotiation tactics successful, even as he tried to hype the deal with made-for-TV drama and invented measures, sparking questions and confusion. Mexico’s leaders showed they weren’t willing to play along.

The White House did not respond to inquiries about Trump’s tweets.

But the president appeared to be making a reference to talks over how Mexico handles Central American migrants who travel through the country to claim asylum in the U.S.

The Trump administration has been trying to pressure Mexico to enter into a “safe third country” agreement, which would deem Mexico a safe place for migrants and make it harder for asylum seekers who pass through the country to wait until they reach American soil to file a claim.

But the deal announced Friday made no mention of the issue.

A senior administration official, speaking on condition of anonymity to share details of closed-door talks, said Mexico had expressed openness to the idea during negotiations, and said the two countries would continue to discuss the issue over the coming months.

Mexico has been insistent that it has not agreed to the provision, which would require approval from local lawmakers.

Instead, Ebrard said during a press conference in Mexico City Monday, if the deal announced Friday does not begin to drive down migrant numbers in the next 45 days, officials will open up new discussions in which the U.S. will again push for the safe third country measure and Mexico will propose establishing a regional refuge system in conjunction with the United Nations and the governments of Guatemala, Panama and Brazil — three countries that are often starting points for migrants headed to the U.S.

“They wanted something else totally different … to be signed,” Ebrard said Monday. “But that is what there is here. There is no other thing.” As for Trump’s tweets hyping a secret measure? Ebrard said he’d provided a full account for transparency’s sake.

A regional asylum compact like the one Ebrard described could have major implications for asylum seekers, said Sarah Pierce, an analyst at the nonpartisan Migration Policy Institute.

“While in theory such an agreement would share the burden of refugee flows across several countries, in reality it could significantly worsen the current situation if the designated countries are unable or unwilling to properly accept and integrate the migrants,” she said.

Over the weekend, Trump also claimed another new element of the deal, tweeting that Mexico had “AGREED TO IMMEDIATELY BEGIN BUYING LARGE QUANTITIES OF AGRICULTURAL PRODUCT FROM OUR GREAT PATRIOT FARMERS!” The administration has yet to reveal the details of any such provision, and Mexican officials say no agreement on farm goods was reached as part of the talks.

Ebrard told reporters the talks had focused on migration, not commerce, and hypothesized that Trump was calculating an economic boost resulting from his decision not to implement the tariffs.

“We do not have a specific agreement on products of that nature,” he said.

Trump has spent the days since Friday’s announcement defending the scope of the deal.

That includes a commitment by Mexico to deploy its new National Guard to the country’s southern border with Guatemala — something the country already intended to do before Trump’s latest threat. It also includes an agreement to publicly support the expansion of a program under which some asylum seekers are returned to Mexico as they wait out their cases. U.S. officials had been working to expand the program, which has led to the return of about 11,000 to Mexico without Mexico’s public embrace.

Trump and other administration officials, however, say Mexico made major concessions and have credited his threat to slap a 5% tax on all Mexican goods if the country didn’t immediately agree to do more to stem the flow of Central American migrants across the U.S. southern border. Without the threat, Trump has insisted, Mexico never would have acted.

“It was all done because of the tariffs and because of the relationship that we have with Mexico,” he told reporters Monday, following a call-in interview with CNBC Monday morning in which he said officials had “talked about it for months and months and months,” but couldn’t reach agreement until the threat.

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Verza reported from Mexico City.