Transcript for Trump points to big, secret announcement in deal with Mexico
Tonight, president trump is defending his deal with Mexico as a great success, after claims much of what was agreed to had already been in the works for some time. ABC's chief white house correspondent Jonathan Karl. Reporter: President trump is insisting his threat to impose tariffs won big concessions from Mexico to stop the flow of migrants across the u.s./mexican border. This is something the U.S. Has been trying to get for over 20 years with Mexico. They've never been able to do it. As soon as I put tariffs on the table, it was done, it took two days. Reporter: But the program seems to be made of up of measures Mexico actually agreed to months ago, including a plan to keep migrants waiting in Mexico while their applications for asylum in the U.S. Are although U.S. Officials say that plan has been greatly expanded. The president says there is more, and that it will soon be announced. We purposely said we wouldn't mention it for a little while. It's going to be brought up because it has to be brought by their legislative body. It's got to be taken to a vote. Reporter: But the Mexican foreign minister says there is no secret agreement beyond what's already been made public. Late today, the president was asked directly about that contradiction. Why are the Mexicans denying it then? I don't think they'll be denying it very long. It's all done. Jon Karl with us live at the white house tonight. And Jon, president trump is still threatening to use tariffs in the future if he doesn't see change at the border? Reporter: He sure is. U.S. Officials say the key question here, the bottom line question, is whether Mexico's actions reduce the flow of migrants across the U.S. Border. They say they will monitor the numbers and if the number crossing the border illegally does not significantly go down over the next 45 to 90 days, the tariffs are very much back on the table. Jon Karl starting another week at the white house. Jon, thank you.
This transcript has been automatically generated and may not be 100% accurate.