The Democratic senator's comments came two days after the USA and Mexico reached a deal to avert the five-percent tariffs Trump had threatened on all imports from Mexico, a move economists said would have had a devastating impact in both countries.
"We told them - I think it was the most important achievement of the negotiations - "let's set a time period to see if what Mexico is proposing will work, and if not, we'll sit down and see what additional measures" are needed, he said.
"The New York Times wrote a story like I already made the deal, it's nonsense, we talked about it for months and months and they wouldn't get there and we just said, hey look if you don't get there we're just going to have to charge you hundreds of billions of dollars in taxes", Trump said.
President Trump on Tuesday doubled down on his claim that he had cut a secret deal with Mexico to stem illegal immigration - even waving a piece of paper he said it was written on - but wouldn't reveal any details.
President López Obrador's government also said that it would take in several thousand people seeking asylum in the U.S. while their cases were...
In a pair of tweets Monday morning, Trump claimed that Mexico had agreed to action beyond what was outlined in the Friday announcement, teasing that more would be revealed soon.
Over the weekend and on Monday, 10 June, Trump made several statements regarding the United States' ongoing trade war with China, referencing his perceived success of his threats against Mexico as evidence that the tariffs he has imposed on China are working to change the two countries' trading status.
"Outside of what I have just explained, there is no agreement", Mexico's Foreign Affairs Minister Marcelo Ebrard said on Monday.
Nevertheless, Ebrard said other Latin American countries should share the burden, something that the United States appeared to have agreed to.
USA producers complain that French wines get to U.S. shelves "for nothing", he said, adding that "it's not fair and we'll do something about it".
Trump has dangled the prospect of renewing his tariff threat if the US ally doesn't cooperate to his liking. "We have an agreement that, if they implement, will be effective".
Mexico continues to block Washington's plan of pushing it towards a "safe third country" agreement.
Lopez Obrador, who was present at the press conference, reiterated his approval of the agreement, saying dialogue prevailed over confrontation.
However as USA wine journalist Christy Canterbury MW pointed out in a blog on the topic following the President's twitter outburst last November, the issue is more complex than simply blaming "unfair" "French" tariffs.
According to the deal, Mexico agreed to deploy 6,000 National Guard troops along its border with Guatemala. "So we didn't bring it up, but most people know that answer". "American products are not submitted to a distinct duty but to the same duties as all third countries", Briand said.
But Mexico faces huge pressure to deliver immediate results at the US-Mexican border, where American officials detained 144,000 migrants in May, up 32 percent from April - including a record 89,000 in families.