Tensions between the US and Mexico continued on Friday, with President Donald Trump saying Mexico “has taken advantage of the US for long enough” and no clear indication the diplomatic standoff was close to a resolution.

Trump said he spoke with Mexican President Enrique Pena Nieto on the phone for more than an hour. He described the conversation as “very, very friendly” but again described the trade relationship in stark terms. 

“I have been very strong on Mexico,” he said at a press conference with British Prime Minister Teresa May. “I have great respect for Mexico.” Trump then added, “Mexico has out-negotiated us and beat us to a pulp. They’ve made us look foolish.”

Earlier Friday, in comments to Mexican television network Televisa, Mexico’s Economy Minister Ildefonso Guajardo said talks over trade and other issues had reached an “impasse.” Speaking after a two-day visit to Washington to meet with US officials, he said Trump’s decision to build a wall along the US-Mexico border and his public claims that Mexico would pay for it had stalled negotiations. 

“We cannot reach a solution if the issue of the wall is not resolved with a clear indication that Mexico is not paying for it,” Guajardo said.

A day after Mexican President Enrique Peña Nieto cancelled a planned meeting with Trump in Washington, the US president again took aim at trade ties between the two countries. 

“Mexico has take advantage of the US for long enough,” Trump tweeted. “Massive trade deficits & little help on the very weak border must change, NOW!”

In response to Peña Nieto cancelling the trip, Trump officials floated the idea of a possible 20% tax on Mexican imports. 

Mexico’s Foreign Minister Luis Videgaray dismissed the proposal. “A tax on imports of Mexican products to the United States in no way means Mexico will pay for the wall,” he told reporters in Washington on Thursday. “American consumers will end up paying for it –with higher prices for avocados, washing machines and televisions,” he said, referring to some of Mexico’s leading exports. 

Kellyanne Conway, a Trump adviser, sought to play down the tensions on Friday. The cancelled meeting between the two leaders does not mean relations have “imploded,” she told Fox News. “This one meeting has been cancelled and that was a mutual cancellation.”

However, in a sign of growing concerns about the diplomatic standoff, Mexican billionaire Carlos Slim was expected to hold a rare press conference in Mexico City on Friday. Slim met with Trump in late December, although the two never publicly said what issues they discussed.

Despite the public rhetoric, Guajardo said officials from the two countries are still in contact. “There is still a level of communication and gives us clear possibilities to find a solution. We’re at a point where there is disagreement over a campaign promise [Trump] made, which Mexico finds unacceptable,” he said.