His pledge to build a border wall and force Mexico to pay for it was a central tenet of President Trump's campaign.
But in a January phone call with Mexican President Enrique Peña Nieto, Trump called the wall "the least important thing we are talking about" and suggested there were other ways to fund it, according to a transcript of the conversation published Thursday by the Washington Post.
"You and I both have a political problem," Trump told Peña Nieto during the call a few days after he took office Jan. 20. "Because you and I are both at a point now where we are both saying we are not to pay for the wall."
Trump proposed that both leaders stop talking publicly about who would pay for wall construction — and threatened to pull out of trade negotiations with Mexico if Peña Nieto continued to tell reporters that Mexico would not fund a wall on its northern border.
"If you are going to say that Mexico is not going to pay for the wall, then I do not want to meet with you guys anymore because I can't live with that," Trump warned Peña Nieto.
"We should both say, 'We will work it out,' " Trump said. "It will work out in the formula somehow."
Peña Nieto, however, wouldn't budge and to this day insists Mexico won't pay for wall — just as Trump insists it will.
The tense conversation between the leaders of allied nations illustrates the high political stakes for both presidents, and the transcript shows both have been less than totally candid about what they said to each other. The transcript in particular has raised eyebrows in Mexico, where Peña Nieto's interactions with Trump have been closely scrutinized.
Some Mexicans, including members of opposition parties who hope to replace Peña Nieto as president when his six-year term ends in 2018, accused Peña Nieto of not standing up to Trump on the issue of the border wall and complained that he remained silent after Trump suggested sending American troops into Mexico to fight drug traffickers.
Peña Nieto came off as "submissive and complacent" on the call, said Jorge Lopez Martin, a spokesman for the right-leaning National Action Party.
"Mexicans must know if our president will follow the orders of a foreigner who hates us, or if he will safeguard the autonomy of the Mexican government that he represents," Lopez told Mexico's Reforma newspaper.
"Where is the defense of our sovereignty?" wrote Agustin Basave, a member of the leftist Democratic Revolution Party, on Twitter. "Trump offered to send troops into Mexico because ours 'are afraid' of narcos, and Peña remained silent."
In January, after small portions of the call were leaked to the Associated Press, the Mexican government fiercely denied reports that Trump had suggested sending American troops to Mexico to fight "bad hombres," with Peña Nieto's spokesman calling such claims "nonsense and a downright lie."
But the transcript obtained by the Washington Post shows Trump did suggest sending American soldiers to Mexico.
"I know this is a tough group of people," Trump said of drug traffickers, "and maybe your military is afraid of them. But our military is not afraid of them, and we will help you with that 100% because it is out of control — totally out of control," Trump said.
Other commentators defended Peña Nieto, saying he did an effective job of not provoking the volatile U.S. president, who in the past has threatened to slap a border tax on all imports from Mexico, a move that could devastate the Mexican economy.
Genaro Lozano, a professor of political science and international relations at the Iberoamerican University in Mexico City, pointed out that Peña Nieto ultimately did not capitulate to Trump's repeated demands that the Mexican leader stop saying publicly that his government would never pay for the wall.
"He was very courageous to publicly defy what the president of the U.S. told him to do," Lozano said. "He treated a bully the way a bully should be treated, by ignoring what the bully demanded."
Lozano said the focus should be on Trump's comments during the conversation, specifically his acknowledgment that in the end, the border wall may not actually be funded by Mexico.
"That's such a big lie to the American voters," Lozano said.
3:35 p.m.: This article has been updated with additional quotes from President Trump and Mexican President Enrique Peña Nieto.